engine problems

i baught an 88 5.0 and it had been sitting for 3 years not touched, there was something wrong with the fuel system due to the motor always duying out after being started, changed the injectors and it ran good no problems, go to start it the next day, it does the same thing when i first baught the car, so i changed the fuel filter, now when i start it, it wont stay running on its own, and i get a lot of backfiring out of the intake manifold. i have no clue what the problem, any help

hmmm sounds to me like the fuel pump.

I am not positive, but I cannot see a fuel pump causing a backfire. Backfires are normally a timing issue, I would think.

Your out of time bud. There are only 2 things I have ever seen cause a backfire out the intake. 1 TIMING! Your distributor is out by more than 1 tooth by the sound of things. Pull #1 cylinder (passinger side nearest radiator) up to TDC, reset the distributor so that the rotor button points directly at the #1 pin in the distributor cap. Then it should fire right up, may have to turn the distributor a little to get it to fire though. Then put a timing light on it and set it to I beleive 10*BTDC. This should fix your problem.

1996 Mustang 4.6 mod motor, came in for spin/ no start.. tried and tried to get her to fire. about the third try to start, backfired out of intake. I realize most common [roblem is timing but in this case it wasnt.. his problem sounded like this one so i gave advice. NGS showed low FP.. pulled pump out installed new pump with sock. And also installed new fpr. Started but ran only for about 3-4 seconds before dying. Installed new security module and programmed key and ran like a charm.

*EDIT* He also stated that he had previous problem with fuel system **

Well that makes about as much sence as the '97 Z28 that came in with the same spin/no start problem. His was a faulty coil wire. Had just enough left to carry spark everynow and then I guess. Never understood why it made it backfire, it would almost try to run backwards. Changed coil wire and it was fine. I guess when a computer gets a weird signal anything can happen.