service engine soon light

I have a 95 monty and the check engine light soon comes on only after I drive it for over a half an hour. When I turn my car off then right back on it goes away till I drive it over a half an hour. Some days it won't even turn on.

You might have an emission problem. It could be a lot of different things, so get the computer scanned for fault codes and from there start your search.

I had the same problem and after GM wanted to redo the entire wiring system. I had no error codes, the system kept reseting and would only come on after driving for a bit then braking hard. Check the "Eng Emis" fuse on the passenger side, underhood fuse cluster. It is a 15amp, mini fuse which also controls your AC Compressor, Engine Emissions sensors, etc. It is prone to get wet and short out. $0.30 is a a lot better then $300! Good luck.