hey guys.
could someone tell me what happens when the O2 sensor works wrong? is there too much fuel consumption? is there black smoke in the rear??
i ask because my iroc is still eating too much fuel. i think it runs 9 miles per gallon. i havent plugged it to the scanner. im trying to figure out what happens.
thanks

 

At the VERY LEAST, I would check the trouble codes. I know that here in the states they sell these "trouble code keys" for like $4 or something like that, but it can be done with a paper clip too. Plugging into it and getting an actual reading on what the sensors are telling the ECM would be ideal. I think going one of these two routes will most likely cost you LESS money than just blindly buying and replacing parts.

To answer your question, I haven't experienced EVERYTHING that can happen with a bad O2, as I have heard of some pretty strange things happening, but in general, you will/can get increased fuel consumption and perhaps a rough idle (maybe more). I know I just did the O2 on my Buick Regal and it smoothed the idle out quite a bit, but I was doing plugs and wires the same time too, so who knows.

Black smoke coming out the rear would seem to indicate your car is running very rich, and I would be hesitant to blame just an O2 sensor, so I think you have other issues at hand.

There are guidelines on this board as to what a good tuneup for these cars entails. I would recommend considering these ideas, as well as finding out what is going on with the ECM (one way or another). Good luck with everything.