scan for codes and check fuel pressure first. if it's an lt! or LT4 engine it may be a distributor problem.

Replaced fuel pump, pressure stays up over 35psi for over an hour. It is a lt1. replaced the tempeture sensor in water pump twice. It does not throw a code and none showing. Distributor (opti spark) was replaced 6 months ago. All new plugs and wires, new MAP. new thermostat.

Thanks for your reply, should have given you this additional infromation to start with. Sorry

Thanks for any help you can give me

Ron

fuel pressure should be 41-47psi. also try cleaning throttle plate on both sides and iac hole, they get gummy from oil. but i really think fuel pressure is your problem.

fuel pressure is 42psi when engine started. after sitting for hour it is at 35. That's when it is hard to start. Would 35 psi cause that problem and if so what would cause the leak. I have check the pressure regulator seems fine, no gas in line indicating it is leaking, check all fuel lines, no leakage, check at the pump and find no leakage..

Thanks again for your help

see what the pressure is after about 2 minutes of engine shutoff, if it' s still at 42 then drops to 35 it my be an injector is leaking and you could have apro runinjector cleaner through it. also scan for codes to see if there are any lingering ones.

pressure will stay at 42 for approximately 30 to 45 minutes then it will drop to about 35 lbs over about 1 1/2 hours after engine turned off. I have multiech injectors and have held them in the rack over a pan to see if any leak with preassure at 42 lbs. Not a drop leaks..Held them for about 15 minutes.. This is one weird situation. I have searched the internet high and low for someone with same issue, but found nothing. I am beginning to wonder if it is the PCM that is causing the problem..

check your coil for resistance, maybe it's to high, other than that i can't think of anything else.

Thanks, I will do that and let you know if it is an issue..