I have a 87 f150 with the fuel injected 5.0, the truck ran great and was parked for about 2 years, now it will not stay running. It will crank right up very easily, idle smooth for a minute or less then just die like you cut it off. Here is a list of what I have done sofar and nothing has helped
replaced both fuel pumps (only has 1 tank)
Replaced fuel tank
Replaced fuel filter and pressure regulator
replaced fuel injectors
installed msd coil, distributor cap and rotor
installed ford racing plug wires
new Motorcraft plugs
new throttle position sensor
I have a new o2 sensor but haven't installed yet

Truck so has egr deleted, it is plugged at the lower and upper intake points, and the plug is just tied up to the harness, don't believe this is a problem since it has been that way even when it was running.

I am really stumped with this and any help is greatly appreciated.. thanks!

 

Starts. Goes to fast idle and then dies when dropping to normal idle speed? Is the IAC working?

 

I'm gonna try to clean the iac tomorrow, maybe that will help.

 

As soon as you crank it you can give it gas and it revs good, then when it returns to idle it shuts off after a few seconds, could iac cause that too?

 

Yes.

IAC - Idle Air Control

 

Well I installed a brand new iac today and no luck. Still has the same symptoms

 

When I first got my '89 it would shut off while driving. It would stumble and die. Turned out to be corroded wiring at the fuel pump relay (next to the air box).

 

i have had that same trouble on a 5.0 and a 5.8. the 5.0 has new motor and new everything, still will die when cold only at start up, if you keep it running for a few seconds it will not die until cold again. even tried a new computer, same thing... beats me. the 5.8 idles high at start up and then will slow down...no help from me, sorry.

 

I have a set of headers to install, I have put this off since it won't run, but I am going to cut the exhaust loose tomorrow, thinking it's possible the exhaust is partially stopped up, the whole underside of the truck was covered with dirt dober nests, possible the ventured into the exhaust?

 

Well I may have found the issue. I pulled the o2 sensor out before cutting the exhaust loose. Figured this would let it breathe a little better. It cranks up idles perfect revs fine, has been idling for about 20 minutes now with no issues. So I'm guessing either the cat, or muffler is stopped up.