I have a 1995 Chevrolet Camaro Z28, with a new LT1 engine in it. I have had a problem for a little while now. The car hesitates to go often and unexpectedly dies, usually when I come to a stop. The car has 128,000 miles on it, not sure if o2 sensors have ever been changed. It was backfiring and sputtering until I changed the fuel filter about 6 months ago, it seems to turn something off and Service engine light comes on, had done that for a few months, but the service engine soon light eventaully came on and was on until a couple of days ago. I never went to see what the code for the service engine soon light was. After the service engine soon light turned back off the problem came back. But never had the problem while the service engine soon light was on. I believe that it is the o2 sensors, if I accelerate too fast it stops accelerating until I let go of the gas. Gas economy is bad, but I am not sure what it is supposed to be, I get about 10-12 mpg. How many o2 sensors are there and is that the problem? I have really bad emmissions, u can't go in back of car without choking after a few seconds. I am planning on having the o2 sensors replaced in the morning, but I am not sure if that is the problem. Someone please help me.....



Corey

 

You have two pre-cat O2 sensors, one for each bank of the engine.

It would make it a lot easier to diagnose if you just had the PCM scanned for codes. The code will be stored even it the SES light is off. Eliminates a lot of guessing.

If its running rich, there could be several possible causes:

-faulty O2 sensors
-exhaust leaks before the O2 sensors
-excessive misfires due to other causes
-leaking fuel injector
-excessive fuel pressure

Sounds like the PCM is fighting to control the A/F ratio using the long term fuel corrections, and the long terms are maxing out and setting the code. But again.... the diagnostic codes are there to help you. I can't understand why you would drive for 6+ months with the engine running like that, and never have the PCM scanned.

To clarify, you mention its a new engine, but then appear to have been running it for quite a while. When was the engine replaced? Did the previous engine exhibit the same problems? Who built the engine? Is it "stock" or modified? Have you checked for bad plugs and wires? Have you verified there are no vacuum leaks? Other than change the fuel filter, what have you tried?

 

follow the advice above.


also you can try un hooking the battery to reset the computer. once you hook it back up see how it drives for the first few minutes. the car runs with using the o2 sensors for a while till they warm up. you need to reset the computer because it will remember how much it had to adjust last time it was ran and it will add that to it while its warming up

 

But don't reset the PCM until you have had it scanned for codes, or you will lose the stored codes.