I have a 86 f-150 with a 302 FI V8. Here is a summary: My truck kept stalling/loosing all power whenever it warmed up to normal Temp. and whenever I went over 3,000 RPM. I had fuel pump replaced in engine, didn't work, then I replaced the one in the tank. It now runs better under a load (over 3,000 rpm) but it will not run at idle at normal temperature now??

I checked the battery and alternator and both are fine. Once the motor cools back down, it will crank again and run fine until the engine warms up to normal temperature? Does anyone have any ideas what this might be?

Thank You!!!

 

I would check your cat converter. that is what it sounds like to me.

 

The fact that changing the fuel pump made a difference. Hmmm. Fuel filter may be a problem. A muffler shop can check the cat. for back pressure. Make sure you know what the approximate pressure should be. I can't remember. Someone on FTE will know. Does the engine quit when the temp gauge is at a specific place?

 

The Cat was gutted a long time ago and the fuel filters were just replace 2 weeks ago. The motor seems to die when the temp. gauge needle warms up to the exact middle of the guage level?

Any more suggestions?

Thanks

 

Sounds like a bad ignition control module or coil to me. I'd pull em both and get them checked.

 

yea no doubt on that. i would prolly check the coil first.

 

my bronco does a similar thing, i have replaced all ignition components exept the coil and it is still crapping out. i recently rebuilt the carb, the fuel pump and such was replaced last year, both filters are new. i have done everything except shoot it

 

As the coil warms up the internals expand and do not work efficiently or at all for that matter, coils are relativly cheap and easy to replace.