My engine is hard to start?

2000 Blazer 4.3 Hard start hot. After sitting overnight it will start ok. After reaching operating temp, if you shut it off and attempt to start with in a few minutes or longer it is a prolonged crank. Ign coil was replaced. Tested fuel pressure with KOEO, 60 psi and then drops to about 55 psi after regulator opens. Fuel pressure when running or when problem occurs is aound 55 psi. I have found that the fuel pressure will bleed down after a short amount of time with the KOEO or key off. However when the problem occurs fuel pressure is ok. Tested with pedal to the floor "ecm clear out condition" when cranking, made no difference.

I will try restricting the return line and monitor pressure. Do you have any insight or info regarding why it woud start ok after sitting over night. Even when it is a hard start issue, fuel pressure is w/ in spec. Also if I shut it off and crank it again w/ in a few seconds it stats ok, but if it sits for more than 5-10 minutes or longer it becomesa hards start. Do you think the Ign module could cause this? The Ign coil has been replaced the cap/rotor has been checked. (Performed a tune up last year). I'm just not 100% sure on testing the Ign Module.

With the key on engine off the pressure will quickly go to about 60 psi then drop quickly about 5 psi when the regulator opens (I'm assuming). After that the pressure will continue to drop to 0 psi with in a minute or two. It's odd that it if you shut it off for only a second or two and crank, it will start ok, but if you let it sit for 5 - 10 minutes or longer it becomes an issue. Also it starts ok if it sits overnight cold.

Thanks
-Mark

I am trying to research what is wrong. If it sits overnight or at least for a few hours it will start and run fine but drive it five minutes up the road turn it off to go in the store or something and have to turn it over multiple times to get it to start back up again. We have replaced so many things in the past few months and the ignition coil yesterday and still cannot find the problem. Thanks for any help you can offer.

The fuel pump was replaced a few months ago and the problem did not start until well after.

This vehicle seems like it is not getting fuel in the morning, to the point that one time it has required a jumpstart. Once running. It will easilt turn on and off all day long. But if it sits over night, it has the same problem in the morning. We have eliminated the battery as an issue. And using a starting fluid deems the same hard starting results.I have checked the battery and connections and alternator and the load test thing and all shows to be fine.I really am clueless. This vehicle got a new fuel pump only a year ago when the vehicle just died pulling into a store. Other than another fuel filter, I am quite clueless. Please help. Bobby

My car lost all power the other day so I replaced the battery and all was fine for a couple of weeks and then one day the engine would not start and sounded like it did not have fuel. The next day I checked and it started immediately so I took it to a mechanic and he checked the pressure and was ok (45 - 50 psi). He said it may be the fuel pump and suggested I carry a small container with fuel and if it happened again I should pour a small amount of fuel in the intake and if it worked it would indicate the fuel pump. I've been driving for a whole week without incident and today it happened again after driving about 15 miles. I tried putting some fuel in the intake and for a very short moment it started the engine but quickly dropped off as soon as I released the accelerator. What other things should I look for?