i have a 1989 Audi 90. The car runs but when it warms up it almost acts like it loads up..and wont let you rev the motor..ive been told that i should check the valves wich i did and there seems to be nothing wrong there..had the computer sent away and tested and everything seems fine there...and then i took out the spark plugs and they are blak like there carbon fouled and running rich...i also had it looked at and was told that 2 cylinders were low on compression...so this leads me to belive that i need to re ring it or is there something else i should do???does any one know what my problem is?

 

You might put oil down the spark plug holes to see if
the compression rises. If it rises, the rings are bad.
If not it's the valves.

 

You may be experiencing an issue with the oxygen sensor. It is only used to determine fuel delivery when the engine is warm. If its reading poorly the engine can start cold ok, but run poorly when its warmed up. Another possiblitly is a bad coolant temp sensor. If there was a mechancial issue, i would expect the engine to run poorly all the time.

 

The temp. sensor would make sence because when the car warms up the temp guage comes on....ill have to replace that and then go from there....thanks