1988 Pontiac Firebird car wont stay running

1988 PONTIAC FIREBIRD
150,000 MILES • V8 • 2WD • MANUAL
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GBRADLEYB
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HI, i have an 88 firebird formula with a 305 TPI engine. The car will start up but it will die almost immediately. It will run really rough tho if i sit in there and pulsate the gas pedal really fast, but it dies a couple seconds after i stop. It also backfires a lot out of the intake.

In trying to solve this problem i have:

replaced the spark plugs, plug wires, vacuum lines, fuel pump, distributor cap, rotor, and fuel filter.

also, i tested to see if the car ran when i hooked up an ecm off of another 305 firebird and that made no difference.

and i replaced another thing that said "ac spark plug" on it, it was located under the passenger side panel.

also, i have unhooked the fuel line at the fuel filter and it is getting plenty of fuel there, and i also tried to jump the fuel pump relay and make the fuel pump run constantly, but that did not help either.

none of these things has helpled it run better. please help me.
Feb 21, 2009 at 7:13 PM
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RASMATAZ
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Check the fuel pressure with a fuel pressure tester designed for your fuel system and comeback the with readings this is where we start.
Feb 21, 2009 at 11:02 PM
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GBRADLEYB
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i checked the pressure and it was only reading around a max of 15psi. shouldnt it be around 30-40 on the TPI
Feb 22, 2009 at 3:13 PM
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RASMATAZ
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That's too low replace the fuel pump it should have been 30-44psi if its okay
Feb 22, 2009 at 3:31 PM
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GBRADLEYB
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alright, i replaced the fuel pump and it is getting around 40 psi now. it runs really good when i have the gas pedal pressed down slightly, or a lot, but when it is just sitting there idling, it is really rough, it idles really low, and will sometimes die
Feb 24, 2009 at 11:29 AM
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RASMATAZ
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Find the idle air control valve and clean it out and see what happens if its continues do the same thing with the EGR valve
Feb 24, 2009 at 3:49 PM
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GBRADLEYB
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I went out and searched for the IAC valve, and couldn't find it. Where would that be located?

But i went out and started it up and it was idling alright. but after like 20 seconds, it started idling roughly, and i heard what sounded like a POP!! coming from somewhere round the gas tank, maybe inside it?, but the fuel pump still ran the same, but i couldnt get the car to start after that
Feb 25, 2009 at 5:21 PM
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RASMATAZ
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Check the fuel pressure to rule out the fuel pump
Feb 25, 2009 at 5:27 PM
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GBRADLEYB
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aright i checked the fuel pressure again and it is now reading zero. but i can still hear the fuel pump running
Feb 27, 2009 at 12:14 PM
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RASMATAZ
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The fuel pump is no good-its not producing pressure
Feb 27, 2009 at 4:58 PM
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GBRADLEYB
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but it's brand new, and it just worked the other day.


could the popping have to do with the pressure in the tank, cuz i read on a site that if the pressure regulating thing isn't working then you could get that pop sound, and it could not let the pump put out fuel cuz it has to fight the pressure.

does this sound reasonable, or do u think i need to get my money back for the pump?
Mar 2, 2009 at 7:37 PM
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RASMATAZ
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Check the voltage on the fuel pump connector and do a ground check on it
Mar 2, 2009 at 7:44 PM
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GBRADLEYB
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i pulled my fuel pump assembly out of the tank, and the rubber fuel line going from the pump to the metal line that leads out of the tank was split completely down the side. It was an old line. i replaced it, but how would i find out if there is a blockage causing the line to burst, because i don't want to kill my pump.
Mar 4, 2009 at 5:23 PM
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