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rough idle & acceleration

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  #1  
Old 10-16-2008, 09:23 PM
flood's Avatar
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Default rough idle & acceleration

Hey guys, I have an 02 1.8t B6 and I late3y my engine started acting up on me. All of sudden my car started idling rough and shaking while accelerating. I checked the spark plugs and ignition coils and they're fine plus I don't have a CEL.

The strange thing is that it gets better and the vibration isn't that bad but at other times it shakes like crazy. Right now it idles a little rough and rides smooth until I get around 40 mph then it gets a little rough. A week ago, it was bad and it felt like engine was going to fall apart at any speed.

It's not the suspension or wheels because the car is fine when i coast on the highway. it's just the acceleration that's bad.

Any ideas? engine mounts maybe? How do I check if one of the engine mounts crapped out?
 
  #2  
Old 10-17-2008, 02:22 AM
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check to see if there is any fluid leaking out of the mounts. should be a red goo

and your car could have thrown a code but not triggered a CEL. always best to check it anyways
 
  #3  
Old 10-17-2008, 06:17 PM
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i'd say vacuum leak... 1.8t is known for them.

but its never a violent shake tho.
 
  #4  
Old 10-20-2008, 06:37 PM
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Did you check your coils when they were hot? Did you ohm out your injectors as well (while hot)?You can have a bad coil/injector that can ohm out ok if its cool. There are a number of reasons why, the construction of both consist of a wound coil of conductor that leads itself to high potential of intermittent shorts and poor contacts directly related to heat. I've never had an injector go on my Audi(I have had three coils fail) but have had other cars that would display the exact symptoms you describe and it usually was either a coil or an injector. Usually if one of these is intermittently failing the engine will usually perform well on start up and up to the point heat saturates the component. Just something else to consider. Good luck let us know what you find out.
 

Last edited by krystallbluea4; 10-20-2008 at 06:46 PM.
  #5  
Old 10-22-2008, 10:04 PM
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i have the exact same problem and it actually is my mounts
 
  #6  
Old 10-23-2008, 03:05 PM
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Look under your car and inside the engine bay... U should see some unusualy liquid near your engie mounts, if yes-then your engine mounts went bad.
Usually bad coils or vacuum leak would cause a CEL. Also, check your snub mount just in a case
 
  #7  
Old 10-23-2008, 07:04 PM
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ya I just changed all 4 ignition coils, sadly I need 3 mounts but they're hard to find for a good price so far the cheapest I found is $300 for all the mounts do you know of a good place I can get them?
 
  #8  
Old 10-23-2008, 07:13 PM
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What is CEL?
 
  #9  
Old 10-23-2008, 07:26 PM
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CEL = Check Engine Light

blinking = bad bad
not blinking = bad but ok
 
  #10  
Old 02-23-2009, 03:32 PM
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Im having the exact same problem .. I thought it was a coil pack so i replaced all 4 along with my spark plugs and sadly the vibration is still there.

Whats strange is the vibration is there during idle only when the shifter is in drive or reverse.. when its in neutral or park - no vibration.

When the engine is cold, the vibration is worse on idle, but not so bad under acceleration, but when the engine is warm the vibration is not so bad in idle but very bad during acceleration between 60-80 mph.

I looked at the engine mounts and they look fine. I did notice yesterday while i was changing the brakes that the cv boot is broken, but it looked clean and isnt making any strange noises.

I was thinking of putting a jack under the motor to see if the vibration is still there on idle to see if its the motor mounts..

any other ideas to diagnose the problem?
 


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