# 2002 VW Beetle 1.8L Turbo - Engine puttering, misfiring, rough idle



## kirklogan (Sep 7, 2014)

We have a 2002 VW New Beetle with the 1.8L turbo. 

The car is basically un-derivable at the moment. The car suddenly became hard to start and felt like it was struggling to turn over. 

Once on, the engine runs very rough wile idling, RPMs jumping up and down and never settling. Giving it steady gas seems to make it run fine, once enough gas is applied. (too little and it continues to stutter).

We only purchased the car recently and dont have any service records for it. So far we have replaced the Throttle Body, Upstream and downstream O2 sensors, and today a fuel pump. (getting expensive here). 
I checked the timing belt and it appears to be fairly new and feels fine.

Were really out of ideas here and were hoping for some input from the community. 

If there are any details which i have neglected, please just ask and i will provide them.


Thanks in advance!


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## Gdimovski (Aug 25, 2007)

getting any error codes?


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## billymade (Jan 29, 2008)

A VERY common issue; on the 1.8Ts is the coil packs failing (based upon the way the engine is acting; it sounds like a classic coil pack failure). These coil packs, were recalled at one point; call your local vw dealer and see if the recall has been done (you may get the coil packs, replaced for free). I would get the car scanned and see what the trouble codes, are. If it ends up being a coil pack or misfire; you can swap the coil pack from one cylinder to another and see if the code/misfire changes to the next cylinder (good diagnostic technique; can be used for injectors as well). If you don't have a vw compatible scanner; you might consider, buying a cheap one, check out the Vgate VS450 on amazon.com or go up to the factory level scan tool with the Ross Tech VCDS. 

Get the car scanned for trouble codes; post up any and all trouble codes, we will do our best to help!


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## kirklogan (Sep 7, 2014)

We had the car checked out and there was a throttle body code. (hence why we replaced it). Im not sure if it went away or not when we put on the new one, but the problem certainly persisted. There was also an O2 sensor code which is why we replaced both of those. Coil packs seems to be the next thing to check. 

Did not know about the recall, thats a great bit of information, thank you! Will keep you posted!


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## kirklogan (Sep 7, 2014)

Still having the same issue. We replaced all the coil packs and plugs and it made no difference.

When we pulled the old plugs out, 3/4 of them were absolutely DRENCHED in gas. dripping wet. 
That tells me that its getting fuel but clearly not burning it as fast as it gets it. Not sure what the next step may be here. Any further ideas before i send it out to the shop?


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## billymade (Jan 29, 2008)

Please; get the car scanned with a VW compatible code scanner/reader; then post up the codes, that you are getting. It will most likely; point you in the right direction of what the problem is. By the way; did you get the throttle body aligned, when they replaced it? I'm wondering; what your fuel pressure is, have you tested it with a fuel pressure gauge and is it to spec? What kind of shop; was doing the work for you, are they familiar or specialize in Volkswagens? :screwy:

Get a scanner; stop throwing parts at the problem, diagnose the problem intelligently! Get the codes; post them here and get some diagnostic equipment, like a fuel pressure gauge (can be rented for free from most auto parts stores) and get a cheap VW scanner like the Vgate VS450 on amazon.com. If you are going to keep this VW; for any length of time, you NEED access to the trouble codes... that these cars throw, many times it will make things a snap to figure out! Don't be beholden; to a VW mechanic or auto parts store, have your own scanner.... so YOU can control your repair process and figure things out on your own, save a TON of money in the process! Get the codes and lets fix this thing! 

You can look up fuel pressure testing and other troubleshooting info; here: http://workshop-manuals.com/volkswagen/


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## kirklogan (Sep 7, 2014)

Ok, I just ordered the VW code scanner you recommended as well as the fuel pressure gauge. 

I did the throttle body replacement myself and was not aware it needed to be aligned. Is this something I can do with the right connector and software, or are we talking extremely expensive stuff here?

Really appreciate the feedback!


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## billymade (Jan 29, 2008)

Hey, traditionally to align the throttle body you would use a tool like VCDS from Ross tech ($250-$350 depending on whether you want to be able to scan the later can bus Vw models) but many believe that you can use a "poor man's throttle body alignment" by turning the ignition on (but not start the engine), then leaving it in the "on" position, for a number of minutes and then you'll hear some noises from the throttle body area (high-pitched whirring noises) and then it will stop making these sounds. The poor man's throttle body alignment while debated ad nauseum on many vw websites, many believe that is good enough to complete the procedure (without the use of a scan tool). I have VCDS and I have had it for many years; so that is the way that I do the throttle body alignment procedure, after cleaning or removing it when servicing the engine. 

http://www.ross-tech.com/vag-com/

On the other issues that you are referring to; I have a hunch that your fuel pump is failing and is on its way out; your pressure testing will confirm a pass or fail condition.

The key to troubleshooting is to do pinpointed testing procedures with the correct diagnostic equipment; then through a process of elimination, hopefully find what the problem is! Keep us posted as your troubleshooting and repair process progresses! 


Sent from my iPhone using Tapatalk


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## billymade (Jan 29, 2008)

You can read more about the poor man's throttle body alignment here: https://www.google.com/search?q=vol...en+poor+man's+throttle+body+alignment&spell=1


Sent from my iPhone using Tapatalk


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## kirklogan (Sep 7, 2014)

Hi guys, my VW code reader came in the mail today and it showed a lot more codes than my standard one.

I have the following codes on the vehicle:

16804: Catalyst System: Bank 1: Efficiency Below Threshold: P0420
17579: Angle Sensor 2 for Throttle Actuator (G188) Implausible Signal : P1171
17704: Error in Mapped Cooling System (usually temp sensor or thermostat) : P1296
17972: Throttle Actuator (J338):Under-Voltage during Basic Setting : P1564
17950: Angle Sensor 1 for throttle actuator (G187): Implausible Signal : P1542
16684: Random/Multiple Cylinder Misfire Detected : P0300
16685: Cylinder 1 Misfire Detected: P0301
16687: Cylinder 3 Misfire Detected: P0303
16686: Cylinder 2 Misfire Detected: P0302
17705: Pressure Drop between Turbo and Throttle Valve (check D.V.!) : P1297

So this car is basically screaming for help and im not sure what to make of all of this. Any further input would be appreciated!


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## billymade (Jan 29, 2008)

Hey, you can look up codes here: 

http://wiki.ross-tech.com/wiki/index.php/Main_Page

You might save the codes that come up and clear all the codes, see what comes back. The codes; remain in memory, until they are cleared. So, many of the codes; are built up over time and some, may have been resolved... when you replaced a number of the parts, that you mentioned. 

This code; maybe of interest, based upon your current running condition: 

http://wiki.ross-tech.com/wiki/index.php/17705/P1297/004759

I am thinking; it would be a good idea, to clean and adapt your throttle body. 

http://wiki.ross-tech.com/wiki/index.php/Throttle_Body_Alignment_(TBA)

Clear the codes; drive it around some and see if any codes, come back and post up those codes!


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## wraithkl626 (Dec 29, 2011)

I had a similar issue a few months ago that I documented here.

Long story short I developed a very bad intermittent misfire across all cylinders with a bunch of random codes and fuel fouled spark plugs after hitting a brick with the front passenger wheel. I fixed the car by removing the maf and map sensors and cleaning them with some CRC maf sensor cleaner. While I had it apart I also cleaned the intercooler inside and out. The car runs better now than when I bought it.


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## turbosnap (Sep 25, 2014)

Check fuel pressure, fuel injectors may be stuck open and leaking, causing the plugs to be wet.


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## Lsmith (Feb 3, 2016)

*I am having the same problem.*

Can you please tell me how you solved this problem. I read that you changed a lot of part in your car and also bought Vgate VS450. But how did you solve the problem? what part did you change from all the codes you got? Any help will be completely appreciated. Thank you.


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## billymade (Jan 29, 2008)

He had a TON of different codes; I would start by scanning your car and posting up the trouble codes. You might start your own thread and fully discuss, what your problems are. If you don't have a scan tool; you can get it scanned for free at most auto parts stores or buy the VAG 401 from amazon.com. Post up those codes and we can go from there, thanks! :wave:


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