I just bought an 89 Firebird Formula 350. On the drive home I "punched it" on the entrance ramp to the freeway and the "check engine light" came on. It stayed on for about 2-3 minutes and went out. After a couple of hours I started the car again and the light came on again for a few minutes and went out. There doesn't appear to be anything wrong with the car. Ideas?
thanks

 

mine does that every once in a while..........i dont worry about it too much ive done alot of modifications.....my guess is it doesnt like my downstream heated o2 sensor

 

Even if momentarily lit the MIL light it probably stored a code. Use the jumper technique to retrieve the code. You will probably get an O2 code, 32 I think(you can get code charts on this site). You probably have a lazy O2 sensor. They have to stay around 5-6 hundred degrees to function properly. Is is fairly common when they get old to do this, or it might be contaminated. You will most likely be OK to run like this, however if it gets worse I would try to replace it. Your air-fuel mix is largely controlled from info from the O2 sensor. Danno, 89 IROC 5.7

 

If not the 02 sensor code, check for vacuum leak. Make sure all the EGR ports are hooked up also.