I'm working on rebuilding a 302 out of a 86 Ford 150 with electronic fuel injection, I have it back together, and it starts and idols great, but if you try to give it gas it acts like it is running out of fuel. The owner said it would act like that if the rear fuel tank was in use. Now it does it in both tanks.....???
When first started it can be driven, however after a block or two it begins doing these irritating actions.
I have changed the fuel filter, I have checked the pressure,all vac lines, dropped the tank to check the screens , and no results .. I can say for a second it seemed like it was better on each check ,but only started these behaviors again .
I checked the manifold vac at idol 18 on the gage, if you give it gas it will go up to 20, 25 and drops back down to 0 and stalls.
I cant figure this out can you help? PLEEEAAZe....

One other question beside help me on this,
should pulling the vac lineof egr valve make any difference in the idol. or if I unplug the egr electrical connector should the check engine light come on,?
There is no vac whats so ever coming from egr silanoid to egr valve should there be ? Please help ...Owner wants his truck back...
Any help would be greatly appretiated......
thanks to all
rangerford87 ( aka jon)

 

I've recently been having the exact same problem with my 1987 F150, 302 engine. Even my Ford dealer hasn't yet been able to isolate the cause, but they think it may be either a bad fuel pump or clogged filter. A friend of mine had similar trouble with his 1988 F150, and it turned out to be a bad portioning valve (the one that switches fuel flow from one tank to the other). When I finally get this problem solved I'll let you know. Please do the same if you find out your problem.

 

Thank you for responding to my post.. It is my to relief that I have slieghed that dragon.FINALLY !!!!
What I did was I cleared all trouble codes from memory, ("careful not to take off negative battery cable while checking trouble codes ,because that would wipe entire memory and that will take 80 start up cycles to get back on track)
Blew out the portioning valve ,cleaning it thouroughly . THen I took the egr valve off and removed all carban changed throttle position sensor, took belts off( ac,smog, ) started it in that state..Then I took it ,after putting belts back on,for a test drive she stumbled once and went on like a champ...I aam glad that is over..Hope this helps you.if you need help post back I will check regularly....