ENGINE RUNNING RICH

QUESTION: I have an 87 IROC 305 TPI which I have owned for about 2 years.  Whenever I run at interstate speeds and then get in a traffic jam, my car will run real rich while it's at idle, in drive with my foot on the brake (that's the only condition that I have experienced it).  I have a factory ECM with the factory PROM and I'm not reading any trouble codes even when it is running rich.  What causes this?  It is embarrasing when I have other people in the car and I have to keep restarting it after it dies. 

Sounds like it could be a bad O2 sensor. They don't have to trip the engine check light to go bad. They are good for only about 30,000 miles. Age also make them deteriorate even without a lot of use. Have a 'scan tool' connected to the ECM connector under the steering wheel to see if the signal from the O2 sensor is varying (cross counts) after warm up, or if the signal from the O2 sensor is 'stuck' at just one voltage lever (no cross counts). The ECM must be in 'closed loop' condition.

There are many factors involved here. A friend of mine had a similar problem and learned that he did not have the same fuel injection system as he thought. Every time he started the car, he was creating the problem. Review your manual. The technique of starting the car in itself can find or make a problem. This is not unique to Camaros. My mom did the same thing with one of her newer cars, since she was used to doing a different routine to start her former daily driver.

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