my car is throwing this code causing my car to run very rich. i had cut off the stock cat because it was clogged and it started running like this. so then i put a high flow cat from a camaro the same year. it still throwing the code and still running rich. how would i decode this problem or is there a certain technique to get rid of it? my car is a 1994 A4 Z28.

 

What code specifically? Did you cut the cat off and run an open exhaust? Do you have a log of the car?

 

There are 6 different O2 sensor codes for your OBD-I 94. Knowing which code you have will make it easier to diagnose it and suggest a fix. There is no relationship between cutting the cat off and an O2 code in an OBD-I car.