OK folks - here's a new one. After approximately 2 hours into my turkey-day trip, the "service engine soon" light came on and stayed on for about 20 miles or so. After another 2 hours, same thing. Oil is OK and everthing seems fine. I can drive around all day in town and this does not occur. Any ideas? And thanks in advance.

 

Codes?

 

Mine does this, but only stays on for a minute or two.

 

My 85 coupe used to do this, but it would come on and then off and then on again during highway driving. At the time I had a straight pipe in place of the catalytic converter and the AIR system was disconnected (the codes were for the EGR system, I believe it was a 32). When I put a new catalytic converter on and reconnected theAIR system, it went away has not come back since (it's been over a year now with no codes). Good luck.

Mike

 

02 sensor might be bad?

 

Need a year model and code or codes. I tried real hard, but my physic powers are not working today. LOL [8D]

 

I have a '92 Camaro RS (with TBI) and the previous owner gutted the cat and installed a Flowmaster exhaust system. Driving around town everything is O.K., but as soon as I get on the highway the SES (service engine soon) light comes ON. When I turn the car off and then back on the SES light of OFF.

The moral of the story is that your catalytic converter may be getting old (which means it is not very effective) and / or you may have O2 sensor(s) problems.

CG

 

I really suspect EGR probs, but need code to verify. [8D]

 

OK, I have not pulled the codes, but am in agreement that probably is EGR related, even though just passed Maryland's emissions test last month. By the way, the car is a 92 w/auto. Did not seem to affect performance or mileage as I averaged a little over 22MPG at highway speeds. Thanks for all the info!