Car is a 2003 grand am v6. I'm losing all my fuel pressure overnight but I'm not even 100% convinced it'* causing my problem. It doesn't matter how many times I "prime" the engine because it doesnt make a difference. Had a fuel gauge hooked up and it went to 0 over night. Turned car on and instantly repressurizes.Half the mornings it doesnt even start. It occasionally starts with a lot of cranking. Both fuel pump and fuel pressure regulator are new. There is no fuel leaks that I can find. I thought maybe a problem with injectors but when it starts it runs and accelerates fine and there is no check engine light on so i dont know if there is a problem with the injectors. I'm lost. Also has new plugs, relay and air filter.

Loses fuel pressure over night? Normal....

What is the pressure when the key is turned on first thing in the morning? How much does it increase when you recycle it? Does it immediately drop when the key is cycled off? Pressure should drop no more than 1-2 psi in 5 minutes....

If it won't start, try spraying carb cleaner into the intake while cranking.......if it starts and runs, but dies as soon as you stop spraying, and pressure is ok, possible injector problem......if it continues to run when you stop spraying, try changing the fuel filter....

Should be checked for codes.....If it doesn't start with carb cleaner, is there spark?

It losing all fuel pressure over night is normal ? Had a few people tell me it shouldn't drop more than 5-10 psi sitting over night.

I don't remember the exact numbers since its been a week since I tested it but everything was just where it was supposed to be fuel pressure wise with the the key on, engine off then turned on ect. I've also never had it not start right up with a fuel pressure gauge hooked up. It only happens at 4am when I have to go for work and not once has it not started right up when trying it when I get home.

I haven't tried starting fluid or checking for a spark when it doesn't start because like I said the problem has only happened in the morning and I'm in an apartment so I don't really have the time then or even the light. I plan to get up early this weekend and I hope it doesn't start so I can check those things you mentioned.

I've also had it ran for codes and there was nothing.

In a perfect world, it shouldn't drop at all......but you could have seepage from an injector, pressure regulator, check valve in fuel pump, etc....if you cycle key, and the pressure doesn't drop in a minute, I wouldn't worry about pressure...

I would try a fuel filter first....when the engine is cold, you need rich mixture for a start....a warm vehicle needs a leaner mixture....

Another possibility is a malfunctioning ECT, coolant sensor....

Does it have to be sprayed into the intake while cranking or can they be one after the other? I sprayed some in then went over and tried to start it and nothing. Can't do it at the same time because i live by myself.

And I hope I sprayed it in the right spot. Took the big hose off, opened the big valve thing on the throttle body with my finger and sprayed it in there.

I sprayed some in, put the tube back on and then tried to start it. Also changing the fuel filter later today.

I got someone to crank it as I sprayed it in and nothing happened.

I've also noticed it that it happens more mornings when its chilly. If I don't try to start it in the morning and let it sit through the day out in the parking lot it always start fine when I try it after getting off work. I don't know if temp could actually have anything to do with it but it seems like it does.

Sorry for all the posts.

After spraying the carb cleaner while cranking it over and having it not start I let it sit for about 15 min with the key on. Went back out there and it took a few times to finally catch but it started. This is so frustrating

Well I mine as well add another message since I can't edit my others.

After it statrted I drove it around my apartment complex. I parked it then went inside and showered because I wanted to go get some food. I go to leave and it doesn't start.

Methinks you have to check for spark when it doesn't start, now.....