I have a 1990 f150 with 5.0 engine and auto transmission its 4wd...my truck will start good and idles great but it will sit and run for about 10 minutes or so then just die like you turned the key off i have changed ignition control module, coil, distributor cap and button, plugs, wires and ignition switch any help here would be greatly appreciated i am stumped with this one im about to change ecu just because i am out of ideas

 

I assume when it dies it will not start back up right away? If that is the case the PIP inside the distributor is most likely bad. The real bummer here is that you cannot buy a decent rebuilt distributor and the aftermarket distributors are junk also. Your best bet is to get a replacement PIP and have someone install it in your current distributor. The distributor must be removed from the engine and disassembled to replace the PIP. Get a genuine Ford replacement PIP if they are still available.

 

It will start back immediately if you turn the key off then start it back but if you leave the ignition on it will not start...you have to turn power off then back on

 

The ignition switch was among the things listed that you replaced. Did you replace the actual electrical part of the switch and not just the key tumbler.?

 

Yes the electrical part was what i was talking about sorry i should have verified but i didn't replace the key tumblers i took it out and they're no burns or anything and it works as it should so i didn't think it was bad should i replace that as well?

 

No need to replace the key tumbler. The reason I asked was a lot of guys replace the key tumbler and assume they replaced the ignition switch.

For your quitting problem I don't know what else to say.

 

Got my truck fixed yesterday i changed distributors and put a new ecm in it not sure which fixed it but it's running good now thanks for helping me on this 1