i have a 1992 passat cl ,when the car is cold it runs great , when it warms up a little the car has a rough idle , ive replaced one bad motor mount and tuned it up , is there something else im missing here ??

 

Petrol or diesel?

 

Regular gas

 

buy a car its not a easy question,especially the car gas

 

When the old petrol engines idles erratically it is typically caused by one or more of the following:
- Air filter element clogged
- Vacuum leak at the throttle body, inlet manifold or associated hoses
- Worn, faulty or incorrectly-gapped spark plugs
- Uneven cylinder compressions
- Timing belt incorrectly tensioned
- Blocked injector/fuel injection system fault

Is the car difficult to start when hot and/or cold?

 

no it fires up easy, hot or cold , my only concern is the rough idle when it gets warm, when cold it idles perfect , when warm starts to get a little rough but doesnt affect performance or gas mileage at all

 

Hmm. When you are driving the car and you have it in 5th gear at approx 80 km/h and you let go of the gas pedal/throttle, can you then feel the engine's rough idle? I have had similar issues with my 93 cl diesel. And that was a loose nut (doesn't know the correct English term for this retaining nut which you cannot screw or unscrew but simply put in to hold it together) on the crankshaft. A week point in the engine for that model... And if you can feel the non-smooth idle when in 5th gear with no foot on the gas, then it might very well be that.

 

dang !!!!!!!!! lol , this is why i love forums like this , i would have never even guessed to start looking there lol, thanks alot i will give that a try

 

having to replace my cat now ,i think this was the problem