I have a 91 Camaro 350. I was driving home when i saw the computer light turn on for a minute and then turn back off. I checked the codes and pulled "code 45". From reading it says that is a rich exhaust. I do have to say I noticed my exhaust has seemed worse than usual lately. The car is running rough and the idle fluctuates. These are all recent issues. I replaced the O2 sensor maybe a month or 2 ago. You think the 02 is bad already? I am wondering what else the issue may be. Any help will be appreciated.

Thanks,
Steve

 

First thing I would do is check the ignition on the side of the engine with the O2 sensor. Start with the plugs and work your way back to the distributor. Check to see if any of the plugs are fouled, cracked, etc. Check the continuity of the wires with a digital multi-meter, look for breaks, burns, etc. Then look at your coil for any external signs of damage or aging performance. Check the cap for any signs of wear on the terminals, carbon tracking, cracks, etc.

My guess is that you have an ignition problem and the fuel is not being burned in one or more cylinders, which is leading the computer to believe you're running rich. The rough idle is another indicator.

 

Thank you for the input. I checked the plugs and they look fine. I checked the TPS sensor as well and the voltage was in the correct range and did not have any spikes when i turned the lever. The coil is less than a year old. I am thinking it is the O2 sensor. I am trying to get a hold of a fuel pressure gauge and see if there is a problem there. If you have any other ideas i am listening.

 

just some more information about this problem. I notice it only acts up when the engine is warmed up. The car seems normal on cold starts.

 

This may help if you can't find the cause.

Had same problem last year on my low mileage 91 TPI - but don't remember code #.

Have your injectors checked - You don't need to take them out but do a cold and hot ohm reading. If they drop by much when their hot they're no good. I think 15 is a good reading.

When injectors are shorting they can still work okay until they warm up.