fuel issue

Hello, I had a random misfire code for a long time and i finally fixed it. But I replaced the fuel pump which wasn't the problem but it still won't start if the car sits for a few hours. I know it is something to do with the pump because I disconnected the fuel rail and started the car and the lines started pumping out gas. But I let it sit for about an hour and restarted it the same way without the fuel rail attached and nothing. Hooked it back up and nothing. No pump humming or anything. And the pump is brand new. So I lowered the tank to see if there was a pinched line and there wasnt. Tried to start it again and all of a sudden pumping really good. Shut off car and let it sit for about 5 minutes and it ran for about 5 seconds and ran out of gas and wouldnt keep pumping. I dont get it. New pump same thing so i dont think my pump is bad. The sensor next to the pump is new too and the fuse is still good. I thought maybe a ahort in the wire harness but tested it and its good. Any ideas on what it could be that wont let my pump actually work after it sits for a while? Thanks ahead of time.

the car is a 96 gt 2.4 by the way

This sounds like a bad fuel pump relay. Since your pump is new and it works intermittantly it is very possible that the relay is not properly energizing. It is located in the power control center under the hood. Not hard to replace nor is it expensive but I suggest you purchase an OEM relay not aftermarket.

alright ill run and go get one now, i hope this is it, Im sick of trying to get this car moving. Thanks for the help

i unplugged the old one and the pump turned right on and the car started. Im going to wait about an hour and see if it starts again. I put the new one on.

okay i got it all running now except im back to square one. it idled perfect and starts perfect. So I go down the road and as soon as i hit 3rd gear it starts misfiring like crazy again, I cant even rev it and it misfires then too. It weird though because when I releave the fuel pressure it always does this, because i have disconnected fuel lines and replaced the injectors and it always does that until i try to go somewhat fast and it screws up everything. This is what i have replaced so far,
Fuel Pump
Fuel Pump Relay
Fuel Injectors
Fuel Pressure regulator
Before cat o2 sensor
Afer cat o2 sensor
Spark Plugs
Spark Plug boots
Ignition Coil Housing
Both Ignition Coils
Ignition Control Module
Crankshaft Sensor
EGR Valve
Air Temp Sensor
Throttle Postion Sensor
Catalytic Converter
Map Sensor
Vaccum Lines

I dont think this could be a camshaft sensor related problem, so Im out of ideas, I appreciate any help I can get, Im sick of this mess

The one thing you didn't change according to the list is the fuel filter. Now that the pump is running you may have a blocked fuel filter that is restricting flow. If that doesn't fix the issue I suggest that you check the injectors for resistance. When they go bad the resistance gets too high and it will cause the car to misfire and not want to rev. Change the filter first and see what happens. Much cheaper than new injectors.

sorry forgot to put that in the list, its kind of long, but yeah it was changed twice now. Im leaning towards a bad ecm possibly. there is one at a junkyard about an hour away from my house in a you take it out yard thats out of the exact same car except its an automatic, but I dont think that will make a difference. Mine is a 5 speed

okay so i got back under the car today to check out the tank again. lowered it and tried to start the car with it still plugged in and nothing. But then when i disconnected the smallest fuel line (vacuum i believe) then it turned right on with no problems and reved up like a new car. So Im wondering where is the sensor or something on this line that is screwing with the fuel delivery.

That possibility exists but it could have been air locked for some reason and when you pulled it loose it allowed the line to open. As long as it runs the job was a success. Enjoy!