Guys, I've got a real big problem. I've got an '86 F150 4X4, 5.0L EFI. For about the last two weeks it's been hard to start cold both outside & also in heated underground parking. It turns over fine, but you had to put your foot to the floor to have the engine fire. Then it would start, run rough for awhile, then go into fast idle and then run fine. This morning it wouldn't start at all. I checked some sensors & couldn't get a signal from the throttle positioning sensor. I replaced it $89.00 later and still no go. I tried a different ECM computer just for the hell of it & it still won't start.
I've got spark & fuel, so what gives?

 

My 92 302 did the same thing, I thought it was injectors leaking. When you push the pedal to the floor the ECM turns off the injectors. Mine turned out to be a bad cap and rotor. You might give them a look.

Hope this helps