Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Do you have a miss at idle with the transmission in gear?
First off, the fuel pressure should not bleed off in 4.5 hours. You should check the fuel pressure regulator to make sure it is not leaking. Do you have any codes that come up?
Not even a p0300?
Does the check engine light come on when you turn the key to run, and then go out when you start the engine or does it not come on at all?
How bad is the miss?
Do you have a scan tool?