I just replaced the O2 sensors on a 2.8L 1995 Audi 90. It corrected a rich fuel mixture immediately. I am now getting a check engine light come on when the cars coolant temperature is high when idling in traffic just prior to the electric radiator fans engaging. The check engine light only comes on at high temperatiure. The car begins to idle rough when it happens and it smells like it is reverting back to a rich mixture. Could this new problem be related to the temperature sensor, or could I have gotten a defective O2 sensor. If I shut the car off and restart, the check engine light gors off and stays off until the temperatue goes high again. Any experience with this would be appreciated....

 

we need fault codes on these cars "its obd2" its no good telling what you think is happening without the code we would just be guessing on the resolve

 

flash it out and tell us.

 

check for fault codes, check all fuses and ensure the coolant fan is working