My 97 Grand Am 2.4 is getting a low voltage code for O2 sensor upstream anybody had any similair trouble???

Question

Sorry the upstream sensor has maybe a couple thousand miles if that and i cut the cat out and put in test pipe it only does it sometimes and acts likes it not getting gas or too much it will smoke black or grey it uses no oil

Answer 1

If you don't have a cat, that's normal. A low voltage on the sensor means that it's detecting way more oxygen than it should. The cat normally uses that oxygen to burn the unburnt gas out of the exhaust. It's going to make your engine run way too rich.

Answer 2

most common cause is a bad 02 sensor. replace it and clear out the code.