I've been having this strange problem with my 91 Camaro's " service engine soon" light. When starting it up it runs well and everything will be in order but sometimes ( for example my way home from work or on the way there) the light will turn on but only when it's at the point of slowing down off the highway exits. But the thing is, that there's no difference with preformence and runs just as normally as it did first starting up. Does it have to do with my brakes?

 

Get your flash codes and see what it's calling bad. My car comes up with a 32 which is my EGR, and the light doesn't come on until I usually slow down or have been driving for a while. I think the solenoid is bad and not having a catalytic convertor has something to do with it.