For some reason when im idling my car begins to shake or shudder. It does not do it everytime i stop but only sometimes. If anyone knows what this is caused by and how i can fix it please let me know.

 

Typically when that happens to any vehicle, the RPMs are too low, for whatever reason.
You can either turn up the idle or keep the rpms up with the gas pedal (which will supply enough vacuum for the brakes without affecting the air/fuel mixture), or perhaps you just need to clean/replace your air filter.

Good luck.

 

You have a vacuum leak. My car did the same thing because the BOV wouldn't close all the way. At idle I was at -10 in drive for vac and the car would shake. When i got the bov to close, now I have -16 in drive and -19.5 in neutral and she runs very smooth.

Check the vac lines. If you don't have a boost gauge get one.

 

Unless he has a 2.8 then it would do him no good.... What is your car idling at? RPM wise? If you very lightly push the gas pedal to bring them up a bit does it go away?

Josh

 

Could be crapped up plugs too - a seafoam treatment wouldn't hurt.

 

Seafoam FTW!

Plus it puts out a REALLY good smoke screen! HAHA

Josh

 

My S4 seafoam treatment.

http://www.youtube.com/watch?v=8AIjzMAdrJY

josh

 

I guess this should of been the first question to ask him. What kinda a4 do you have?

 

Did Seafoam on a friend's 88 Firebird Formula and it was MUCH worse than that. I had pics but it was a few years ago now.

 

I got a 2000 a4 1.8t Q. It did it right after i filled up the other day but it has not idle that rough since.