# Rough Idle/Sputtering Acceleration



## irongrey (Dec 16, 2009)

Of late, my '09 2.0T CC has been experiencing increased rough idle (used to be only occasionally) and a sputtering feel while accelerating or holding steady at rpms up to about 4k. The car still pulls hard and there does not seem to be any loss of power. But that silky smooth feel is lacking. The "sputtering" to which I refer is fairly subtle. Feels kind of like the rough idle, only while actually driving.

Any ideas? Help.


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## CC'ed (Dec 1, 2009)

Possibilities :
Marginal Ignition Coil
Marginal spark-plug (gap too big?, cracked?)
One injector is partially clogged causing a lean "miss"
Bad MAF causing lean miss
bad Ox sensor causing leam miss
vacuum leak, after the MAF sensor
bum gas
excessive intake valve deposits

Check for codes with VAG-COM, if nothing, then check the measuring blocks ( Fuel trims, Misfire counts....)

How many miles on it?


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## irongrey (Dec 16, 2009)

Thanks for your response CC'ed.

I've got 36k miles. APR stage I for most of it. It does seem that some brands of gas exacerbate the sputtering, but none totally eliminate it. I think it is getting worse.

What are "measuring blocks"?

So who other than a dealer can check VAG-com? Would that be widely available with mechanics who work on VDubs?


Thanks


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## irongrey (Dec 16, 2009)

Any one else have any input or are experiencing similar issues?


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## Boosted2003! (Mar 10, 2009)

I am thinking carbon build up issue.


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## Aonarch (Dec 4, 2006)

OP,

I would go ahead and perform a full 40,000 mile service. Get your codes scanned with VAG-COM. Then get a BGK service done at a legit shop (Carbon cleanup/ injector cleanup). Also you oil, all filters (Oil, fuel, air), and plugs. If you are a DSG at 40,000 you also have the major service as well.

Best bet is to find a service coupon like 20% off and get the dealer to do everything if you cannot.


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## irongrey (Dec 16, 2009)

For those interested, I had my car diagnosed today at the dealership. The error code I was getting was a miss-fire on #1 and they found carbon build up on the throttle body. So they are doing a throttle body and fuel injector cleaning.

I think this my resolve my long standing, intermittent issue with a pulsation feeling I would get under hard acceleration where the power would sort of pulse rather than remain steady.

They asked me what sort of gas I had been using (a few recent threads on this topic) and warned me to stay away from "cheap" gas stations. I mentioned my past suspicions about Valero gas and they confirmed that Valero gas sucks. They recommended to stick with major brands (Shell, Chevron, 76).

I wonder if having APR and Carbonio could have also contributed to this carbon build up.

I am looking forward to seeing how smooth the car is after servicing.

Thanks to those who responded to my question as folks were pretty much right on.


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## vwdrewr (Jul 30, 2009)

irongrey said:


> For those interested, I had my car diagnosed today at the dealership. The error code I was getting was a miss-fire on #1 and they found carbon build up on the throttle body. So they are doing a throttle body and fuel injector cleaning.
> 
> I think this my resolve my long standing, intermittent issue with a pulsation feeling I would get under hard acceleration where the power would sort of pulse rather than remain steady.
> 
> ...


I'm looking forward to your update after the service. I've noticed that mine is surging or stuttering more than it used to; still pulls hard, but not as smooth. I'm approaching 38K mile. I saw a video of the BG intake cleaning being performed on an Audi 2.0 TFSI and it looks like a good product and cleaning procedure. Direct injection engines don't have the gasoline being sprayed on the intake valves and the crankcase venting does cause them to get pretty nasty looking over time. It is probably the carbon build up on the intake valves that is causing the misfire and surging as the engine management tries to adjust.


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## Aonarch (Dec 4, 2006)

*FV-QR*

You can't use ****ty gas in this motor. Look up what TSI means.

Shell 93 or nothing.


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## irongrey (Dec 16, 2009)

Sadly, my car felt exactly the same this morning. Rough idle and sputtering feel at low rpms when cold. Once it warmed up, it was fine. So I guess it wasn't carbon build up. I'm really annoyed. Back to the dealership. Will keep you posted.


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## milan187 (Mar 15, 2009)

i think i've always been getting rough idle on cold startup, maybe not in the winter.

i wonder how normal it is....

keep us posted.


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## zcar4me (May 16, 2011)

This has happened intermittently since I've had my car as well. Pretty much only on the first start of the day. The hesitation is most noticeable with the A/C on.


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## Aonarch (Dec 4, 2006)

*FV-QR*

Anyone else's CC 2.0T shake pretty bad on the first start up?


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## irongrey (Dec 16, 2009)

My car did not used to have the rough idle on a cold start (though it never gets that cold where I live). It did occasionally have a rough idle, but very intermittent and not related to temp. Probably won't get it back to the dealer until late next week.


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## chrisblankenship (May 31, 2011)

*2012*

I have the 2012 CC and have not experienced any problems using 93 octane. I accidentally chose 87 at a recent fill up and noticed hesitation at low rpm. Also, I would try filling up at a newer gas station with premium gas a couple of times to see if this helps. I had a Mazda 626, years ago, and the station that was most convenient was also an older station. The mechanic that worked on my car twice for hesitation and clogged injectors recommended this same test. His explanation was that some older stations tanks are corroded and the decomposing liners were introducing contaminants into the gas that were clogging the injectors. So, I quit fueling up at the older gas stations in my neighborhood and never had the problem again.


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## irongrey (Dec 16, 2009)

Just to be sure, I have spent some time driving in stock mode and the rough idle etc is the same. Still trying to find time to bring my car in. 

My car is definitely sensitive to the particular brand gas I use. 

It is like a previous post said, it only happens on the first start of the day and lasts until the engine is good and warm. Then the rough idle and sputtering cruising at low rpm is gone.


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## irongrey (Dec 16, 2009)

Car is at the dealership. Just got word that they identified a bad fuel injector on #1 and will be replacing it under warrantee. So I will see tomorrow how it feels. really hoping this fixes all the problems I have been having (rough idle, sputtering at low rpm, pulsating feel under WOT in upper gears).

Incidently, I have APR stage I (switched back into stock) and Carbonio and dealer has not made it an issue as fuel injector will be covered under warrantee.


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## zcar4me (May 16, 2011)

irongrey said:


> Car is at the dealership. Just got word that they identified a bad fuel injector on #1 and will be replacing it under warrantee. So I will see tomorrow how it feels. really hoping this fixes all the problems I have been having (rough idle, sputtering at low rpm, pulsating feel under WOT in upper gears).


Thanks, irongrey. I'm going in for my first scheduled service soon, and will be sure to mention this.


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## irongrey (Dec 16, 2009)

So far so good. They replaced the fuel injector and all feels smooth. I looked at their notes and first they swapped out the plug and coils between cylinders 1 and 4 and retested and the problem stayed in cylinder #1. So then they deduced it was the injector. They also noted my aftermarket intake but did not make an issue of it. My apr stage 1 was switched into stock mode and there was no mention of that. I guess this bodes well for people who are chipped and need warrantee work done. 

I had a long conversation with the shop owner about using premium vs regular and he swears there is no real difference. I didn't argue with him but just let him talk. I did tell him I found some gas stations whose gas made my car run with less power and thought maybe those gas stations add more ethanol and that that might be an issue. He recommended to stay away from higher ethanol content gas. 

He could not offer me any real explanation for why an injector would have gone bad.

Anyway, I am just so glad to have the silky smooth engine feel back. In coming days, I will test the engine to see if this solved my other intermittent issue of having a pulsation feeling in upper gears with WOT.


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## bordercitymadman (Jan 13, 2011)

irongrey said:


> So far so good. They replaced the fuel injector and all feels smooth. I looked at their notes and first they swapped out the plug and coils between cylinders 1 and 4 and retested and the problem stayed in cylinder #1. So then they deduced it was the injector. They also noted my aftermarket intake but did not make an issue of it. My apr stage 1 was switched into stock mode and there was no mention of that. I guess this bodes well for people who are chipped and need warrantee work done.
> 
> I had a long conversation with the shop owner about using premium vs regular and he swears there is no real difference. I didn't argue with him but just let him talk. I did tell him I found some gas stations whose gas made my car run with less power and thought maybe those gas stations add more ethanol and that that might be an issue. He recommended to stay away from higher ethanol content gas.
> 
> ...


There are a lot of us interested in these results! keep us posted man! :thumbup:


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## irongrey (Dec 16, 2009)

So after a couple weeks with the new injector, things are better, but i would not say completely resolved. I still get some rough idle on a cold start and a bit of that sputtering feel at low rpms when cold, though both symptoms are somewhat improved. That hiccup I had at 2.5k rpms is pretty much gone, though there still is a bit of a torque spike right there. So I am scratching my head a bit.

I plan to take my car in for its 40k service and will discuss these issues. I will have them check the diverter valve, coils, plugs, etc and maybe they will find something.


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## Epence (Jan 7, 2010)

good to see about the improvement. Are you running stock as for now? Also, i'm sure diverter valve is part of it. It needs to hold booooooooooost.


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## irongrey (Dec 16, 2009)

*No resolution yet*

It has been about a month now with the new injector and things are slowly getting worse. Worsening rough idle, continued intermittent sputtering at low rpms when cold, and weird jerky torque spike right at 2500 rpms (primarily noticeable in 1st and 2nd gears, though not always present). But otherwise, engine feels smooth and powerful above 2500 rpms. 

So I'm still scratching my head. No error codes. At this point, i will have to take it back to the dealer, leave it there overnight so they can drive it from a cold start, and then see what they say. I am starting to wonder whether the replaced fuel injector had anything to do with whatever the underlying issue is given the worsening of all the same symptoms. And this is also following a cleaning of carbon build-up and a 40k service (where all they really did besides check things is to replace the spark plugs).


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## Andus (Apr 13, 2007)

I had that exact same issue with my Jetta and it was a vac leak. Brought it to a VW mechanic and had a smoke test done on the vac system. They found a leak, repaired it, and I haven't had an issue since.


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## irongrey (Dec 16, 2009)

Andus said:


> I had that exact same issue with my Jetta and it was a vac leak. Brought it to a VW mechanic and had a smoke test done on the vac system. They found a leak, repaired it, and I haven't had an issue since.


 Was that a 2.0TSI? So you had a jerky torque spike at a certain rpm? I hope it is somethat that easy to figure out and fix.


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## Docson7 (Jun 23, 2011)

Irongrey,

Are you still having sputtering issues? I also have a 09 VW CC, 6MT with the same issues i.e. sputtering acceleration on the low gears, rough idle, etc. I dropped the car off at the dealership to see if they can locate the problem. The culprit was a faulty throttle position sensor, which was replaced for free via CPO. Now, the car accelerates like it's brand new. Hope this helps.


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## Htrswelcm (Jul 22, 2011)

Docson7 said:


> Irongrey,
> 
> Are you still having sputtering issues? I also have a 09 VW CC, 6MT with the same issues i.e. sputtering acceleration on the low gears, rough idle, etc. I dropped the car off at the dealership to see if they can locate the problem. The culprit was a faulty throttle position sensor, which was replaced for free via CPO. Now, the car accelerates like it's brand new. Hope this helps.


 :thumbup:
This is the same thing that I replaced and posted on here earlier. Hopefully other people will look into this now that the two of us have posted.


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## irongrey (Dec 16, 2009)

Docson7 said:


> Irongrey,
> 
> Are you still having sputtering issues? I also have a 09 VW CC, 6MT with the same issues i.e. sputtering acceleration on the low gears, rough idle, etc. I dropped the car off at the dealership to see if they can locate the problem. The culprit was a faulty throttle position sensor, which was replaced for free via CPO. Now, the car accelerates like it's brand new. Hope this helps.


Yes, my car is fixed. My issues got progressively worse until I was getting misfires on all cylinders and some fault code with the position sensor in the intake manifold. Upon inspection, the intake manifold was the culprit. Some "intake runner" had literally broken off. They replaced the intake manifold and all injectors and now the car accelerates smoothly. Idle is still a bit rough at times, but no big deal. No sputtering. I read about at least two others whose issues came from their intake manifold. Nice to have my car running smoothly after like 4 months of decline.


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## dutchy (Jan 13, 2007)

irongrey said:


> Yes, my car is fixed. My issues got progressively worse until I was getting misfires on all cylinders and some fault code with the position sensor in the intake manifold. Upon inspection, the intake manifold was the culprit. Some "intake runner" had literally broken off. They replaced the intake manifold and all injectors and now the car accelerates smoothly. Idle is still a bit rough at times, but no big deal. No sputtering. I read about at least two others whose issues came from their intake manifold. Nice to have my car running smoothly after like 4 months of decline.


Irongrey,
I have had that issue three times now, and they had to replace my air intake manifold all three times because of same problem, the arm that controls the air intake, snaps off.
I started noticing rough running of engine and the engine lights comes on.
It was twice within my warranty(I purchased extended warranty up to 100k miles) and once after, where after I called VW-usa picked up the tab on material, labor I had to cover.
It has now been 20.000 miles after last change and waiting for it to break down again.
I think after replacing it 3 times in 100k miles makes it a bad design and should be replaced with a better product, the cost to replace is about $890.00.
And like you mentioned the idle is still rough at times, and the dealer says it's normal...


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## irongrey (Dec 16, 2009)

dutchy said:


> Irongrey,
> I have had that issue three times now, and they had to replace my air intake manifold all three times because of same problem, the arm that controls the air intake, snaps off.
> I started noticing rough running of engine and the engine lights comes on.
> It was twice within my warranty(I purchased extended warranty up to 100k miles) and once after, where after I called VW-usa picked up the tab on material, labor I had to cover.
> ...


My dealer told me that there is an updated intake manifold as there was some manufacturing issue with the original one. But he indicated that any 2.0Ts built after the end of '08 should have the new one. But just thought I would mention it so you could check and make sure your dealer is putting on the updated manifold. God, I hope this doesn't happen again. That is an expensive service.


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## wobvintage3 (Jun 10, 2005)

I recently developed a similar issue.. Cold start the car idles rough, I scan and get a miss fire error. I thought for sure it had something to do with APR tune and did the same switching back to stock which didnt fix. Once the car warms up its a non issue. I took it in to the dealer and they said they wouldn't touch it until I reinstalled the stock intake stating the issue could be because of the intake and to return to stock and bring it back in. I have actually had mine stall once in reverse because i didnt let it warm up.. Sad part is my car has 8k miles on it.:facepalm:


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## irongrey (Dec 16, 2009)

wobvintage3 said:


> I recently developed a similar issue.. Cold start the car idles rough, I scan and get a miss fire error. I thought for sure it had something to do with APR tune and did the same switching back to stock which didnt fix. Once the car warms up its a non issue. I took it in to the dealer and they said they wouldn't touch it until I reinstalled the stock intake stating the issue could be because of the intake and to return to stock and bring it back in. I have actually had mine stall once in reverse because i didnt let it warm up.. Sad part is my car has 8k miles on it.:facepalm:


My dealer at one point asked me to reinstall the stock intake but by the time I brought it back in, I had a whole series of new engine faults which led them to the intake manifold. In the end, they did all the work under warrantee while my Carbonio was still installed (b/c of course it had nothing to do with it). But I would have swapped it out just to get everything covered under the warrantee. Do you have the engine hiccup? Any sputtering at low rpms while cold. Rough idling seems to be a common issue and potentially related to any number of issues. When was your car built (does it have the old intake manifold)?


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## xx4u2nvxx (Nov 28, 2010)

irongrey said:


> My dealer at one point asked me to reinstall the stock intake but by the time I brought it back in, I had a whole series of new engine faults which led them to the intake manifold. In the end, they did all the work under warrantee while my Carbonio was still installed (b/c of course it had nothing to do with it). But I would have swapped it out just to get everything covered under the warrantee. Do you have the engine hiccup? Any sputtering at low rpms while cold. Rough idling seems to be a common issue and potentially related to any number of issues. When was your car built (does it have the old intake manifold)?


My car recently started doing this at cold starts, it's subtle but definitely there and doesn't last very long. Guess it's time to schedule a service appt, ugh!


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## wobvintage3 (Jun 10, 2005)

I dont know if I would call it a hiccup.. but upon intial cold start the car revs to 1.1k, drops to .2k and almost stalls and does that a few times before it starts to idle decent. If I rev it a few times it generally helps..


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## irongrey (Dec 16, 2009)

So I've doing some more reading on the 2.0t and found the following page which is very interesting and I think speaks to many of the problems people describe on this and other threads. 

http://www.passatworld.com/forums/7...ompiled-list-common-issues-remedies-2-0t.html 

Not sure if the thread is specifically about the 2.0 TSI or the FSI but probably applies prety well to both. 

Specifically, I think exactly the issue I had was covered as "#7. Tumble flap failure" on the list.


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## whitfilj (Jul 4, 1999)

*Same Issues*

I had the same issue with my 2009 6MT CC. It was diagnosed with carbon buildup in the intake manifold and the dealer cleaned it out. I have 34K miles right now. Not sure it is really fixed. I will give it a couple more days


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## irongrey (Dec 16, 2009)

whitfilj said:


> I had the same issue with my 2009 6MT CC. It was diagnosed with carbon buildup in the intake manifold and the dealer cleaned it out. I have 34K miles right now. Not sure it is really fixed. I will give it a couple more days


Same issues? Can you be more specific?

Keep us updated.


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## whitfilj (Jul 4, 1999)

irongrey said:


> Same issues? Can you be more specific?
> 
> Keep us updated.


Symptoms are rough idle when cold and now check engine light coming on (sometimes flashing) when cold. 

Well the saga continues after a few more weeks. After 1st visit ) paying for the fuel system to be cleaned 2nd visit ) replacing the intake manifold I was still having the same problem and the check engine light kept coming on. I just got it back after the 3rd visit they tried to run three cans of induction cleaner and VW tech line is saying I need a $1000 walnut blasting treatment to clean out the carbon buildup. I have around 1500 miles left on warranty/lease end. I really love this car and was planning on buying it but now I am really frustrated. 
I think I will read through the forums again and take any advice offered!


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## irongrey (Dec 16, 2009)

whitfilj said:


> Symptoms are rough idle when cold and now check engine light coming on (sometimes flashing) when cold.
> 
> Well the saga continues after a few more weeks. After 1st visit ) paying for the fuel system to be cleaned 2nd visit ) replacing the intake manifold I was still having the same problem and the check engine light kept coming on. I just got it back after the 3rd visit they tried to run three cans of induction cleaner and VW tech line is saying I need a $1000 walnut blasting treatment to clean out the carbon buildup. I have around 1500 miles left on warranty/lease end. I really love this car and was planning on buying it but now I am really frustrated.
> I think I will read through the forums again and take any advice offered!


What code is coming up with the check engine light?


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## whitfilj (Jul 4, 1999)

*Finally Back*



irongrey said:


> What code is coming up with the check engine light?


Sorry for being such a flake and dropping back in and out but I have more data.

1) I do not know the code because I did not scan myself. I am a loser!

2) Argued with VWoA about having to pay 1000$ to do the walnut blasting after 3 other visits and $200 to the dealer under warranty in the last month. They came back and said it was a maintenance issue because I was not using Premium (had to really hold my breath there) but they would cover part, the dealer would cover part and I would cover part. I said thank you very much (genuinely) but did note I have used Premium every single time and there are known issues with this engine and I mentioned this site and some others talking about the 2.0 engine. The gentlemen who spoke with me said "we appreciate the input so we can track these issues....." you know the rest. So, I took it back in (time #4) in on Tuesday. 

3) Today I picked it up and from a cold start--BOOM perfect. No sputter, no CEL. I want to wait a couple of days to be sure but I think I got my favorite car back finally!


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## irongrey (Dec 16, 2009)

whitfilj said:


> Sorry for being such a flake and dropping back in and out but I have more data.
> 
> 1) I do not know the code because I did not scan myself. I am a loser!
> 
> ...


I'm glad your car feels better. I'll keep my fingers crossed that your problem is resolved.


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## zcar4me (May 16, 2011)

So was the final result a replacement of the intake manifold, or did they clean it with the walnut blasting?
I also wonder if the new intake manifolds are any different in design than the one's they're replacing.


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## 85122 (Jul 26, 2014)

*runs rough*

I own a 2010 VW C.C 2.0 T. I noticed this morning when I drove to the store that the car is starting to pulling and running a little rough. I have never had problems with the C.C just now. I am going to clean MASS Air flow sensor maybe it will help. This is the first time I owned a German car I love it. I myself have replaced the spark plugs and coil before I changed the DSG tranny fluid and tranny filter, replace air filter, motor oil an filter every 4000 thousand miles . The service engine light turns on every six thousand miles when you have to change motor oil. I change the ignition coils once every year . I dont know what a certified shop who works on VW would charge to measuring blocks but, after reading about the guy who took his vw to the dealer and still does the same thing It makes me wonder. Please if anybody knows what is going on please let me know I would really appreciate it THANKS!!


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## 85122 (Jul 26, 2014)

I own a 2010 VW C.C 2.0 T and starting to have the same problem. I have 120.002 thousand miles on it with no problems till now.


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## 85122 (Jul 26, 2014)

I just want to know after having the dealer clean the valves the for the fourth time if you had anymore problems?. Did the problem came back ?


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## 85122 (Jul 26, 2014)

*Sea foam*

I'm wondering if I could treat the engine with seafoam to clean the internal combustion parts. I own a 2010 vw cc 2.0t. My car is starting to run rough. The spark plugs are six months old as well with the ignition coil.


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## angel928 (Aug 10, 2013)

Greetings all,
I've got a 2011 CC, with same symptoms, but no MIL.
From what I read here dealer is little help. I read the previously
Linked thread on passatworld. I don't have access to a vagcom so
Mine will be a trial and error of sorts. Easiest and cheapest is to start with
Coil packs and diverter valve. Car has 90K miles and hasn't needed anything 
Until now. I will report


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## OshKoshBygEOSh (Jul 30, 2017)

Owner of an 09 Eos with 2.0 TSI and my problem was spark plugs. Had a pulsing acceleration at speed though, little different from your rough idle. Weird thing was NO error codes or 'misfire', but it would fail to accel with much gas that put it into boost / above 2.5k rpms. New plugs and she's running like a new 8 yr old  PS mine already had 3 of 4 coils replaced (prior owner, I would've replaced all)


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