# engine vibrate when accelerating



## blue98jettavr6 (Mar 19, 2001)

2.0T FSi in a 2007 A4 front trac with a CVT trans

The engine starts normal and idle 100% smooth (Aside the normal sound and rumble of the 2.0T fsi). 10-30% acceleration still smooth, 50-100% acceleration the engine pull but with lots of vibration. when I let off the acceleration it goes smooth again. No shaking at full stop while in gear (automatic). 

Anyone experience this or have any ideas?


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## yowzaa (Jul 31, 2007)

1. Misfires due to bad coilpack(s) or injector(s), or
2. Bad motor/transmission mount.

a scan for codes could tell you if cylinder misfires are present.


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## dmorrow (Jun 9, 2000)

How many miles on your car? Does it do it when engine is hot/cold or both? Is it as a certain RPM or always? Not familiar with the CVT but can you manually "shift" (I realize you aren't shifting) to change the RPM's and does the problem change?


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## xtravbx (May 21, 2005)

Could be axle/ drive shaft related. Though I haven't heard many people have issues with them on these cars.


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## TCFGLI08 (Apr 6, 2011)

Did you pick up debree on the wheels or axle
Terry


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## xtravbx (May 21, 2005)

TCFGLI08 said:


> Did you pick up debree on the wheels or axle
> Terry



If it was wheel related, he should feel it even when not giving it throttle. So while I wouldn't rule that out - it's doubtful.


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## nogz (Sep 13, 2011)

I'd be interested if you find the solution on this. 

I have the same issue with my VW GTI MK4. I just replaced my plugs and the shaking problem still there (only during acceleration at around 2000-3000 RPM) :banghead: . Checked the coil pack and they are still in good shape. I will soon try to clean my MAF sensor and throttle body I hope that should do the trick.


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## dmorrow (Jun 9, 2000)

When I replaced the N80 valve it got rid of my idle problem and an engine vibration problem from about 3-4000 rpm during reasonably hard acceleration. Going back to stock from Revo Stg. 1 got rid of most of it but once I replaced this valve it got rid of all of it. Put Revo back on and no driveability problems.

My best guess is this valve wasn't allowing enough fuel during hard acceleration.

From ECS - 

_The evaporative emission control valve opens on command to purge fuel vapors from the charcoal canister to the intake manifold, and also to pull a vacuum inside the fuel system to test for vapor leaks. A failed valve can cause undesirable engine performance symptoms and/or store diagnostic trouble codes. Replace yours today to keep your engine running at it's full potential. _

Also bought the valve for less than $25 and did it myself.


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## blue98jettavr6 (Mar 19, 2001)

yowzaa said:


> 1. Misfires due to bad coilpack(s) or injector(s), or
> 2. Bad motor/transmission mount.
> 
> a scan for codes could tell you if cylinder misfires are present.


Going after a set of coilpacks and hoping its not the injectors. Would hate to have to purchase stock injector. Maybe break down a buy a BT kit for the GLi and move the stock injectors over to the A4.
Also no misfire codes. changed a snub mount and backed off on a trans mount as I see little to no play.


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## blue98jettavr6 (Mar 19, 2001)

dmorrow said:


> How many miles on your car? Does it do it when engine is hot/cold or both? Is it as a certain RPM or always? Not familiar with the CVT but can you manually "shift" (I realize you aren't shifting) to change the RPM's and does the problem change?


70,xxx, Idle is typical but slightly more rumble than my GLi with 2.0tFSi, hot and cold same problem, CVT function normal. manual shift sport mode or continues variable doesn't matter it seems to shake when any boost in generated while accelerating.


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## blue98jettavr6 (Mar 19, 2001)

xtravbx said:


> Could be axle/ drive shaft related. Though I haven't heard many people have issues with them on these cars.


Just replaced both axles (Frontrac model) within weeks apart to target the shake. Still shaking however not a total lost as both axle had torn boots.



> When I replaced the N80 valve it got rid of my idle problem and an engine vibration problem from about 3-4000 rpm during reasonably hard acceleration. Going back to stock from Revo Stg. 1 got rid of most of it but once I replaced this valve it got rid of all of it. Put Revo back on and no driveability problems.
> 
> My best guess is this valve wasn't allowing enough fuel during hard acceleration.
> 
> ...


I'm about to click checkout


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## jamesrh (Jan 7, 2014)

did you ever fix the problem ? my gti does the same thing. as soon as i hit 4-5 thousand rpm there is a rumble . i can feel it in the gas pedal. let me know what you find.


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## blue98jettavr6 (Mar 19, 2001)

The evaporator purge valve was change due to ticking noise many miles ago long before the vibration started.




jamesrh said:


> did you ever fix the problem ? my gti does the same thing. as soon as i hit 4-5 thousand rpm there is a rumble . i can feel it in the gas pedal. let me know what you find.


A few weeks ago I took the breather from my 2.0T fsi which runs flawless and put it on the problem 2.0t FSI Audi A4. breather has a one way valve inside that blocks the line to prevent boost from getting from the intake manifold to the valve cover but opens when the engine goes into vacuum allowing the fumes to cycle thru the engine via intake manifold. the part off the A4 is bad allowing airflow in both directions.

So after installing the working breather the shaking was gone away except at full throttle the engine still produced a vibration. I ordered a catch can for the GLi and just today I put that good breather back on the A4 and took it out for a very disappointing drive. The vibration was back but on the last mile before i got back home the vibration was completely gone. So know I've just learned about the rear pcv ( valve cover the compressor) and will have to order one.


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