1992 Chevy Lumina Euro

This vehicle in the past year has developed an annoying habit. After being driven for awhile and then shut off, it will not start again for 3 hours. I have replaced the fuel pump and the ecm, still have the problem. Can anybody help?

This is the 3.1L engine, right? Also, define “won’t start”. Do you mean it cranks but doesn’t fire or doesn’t turn over?

Yeah, 3.1L v6, engine cranks but will not start for 3 hours. You can almost set your watch to it. I had the coil pack tested as well, 3 times. It acts like it is not getting fire to the plugs