Intermitten Problem

I have an '89 F-150 5.0L with 62K miles. Started having an intermitten problem while driving. Sometimes the truck will just cut out and i can get it started again, only for the problem to happen 15 minutes later or so.
Hooked up a fuel gauge and spark plug tester at #1 cylinder and ran it in my driveway until it cut out. Never lost fuel pressure so that rules out the fuel system.

Replaced the original TFI module and swapped a coil only to have the same problem. I'm thinking it's an electrical problem so i "wiggle" tested the wires going to the coil, EEC relay, EEC processor, TFI module, and other connectors while truck was running. Unable to find a fault at this time.

Any suggestions?

Im not sure on a 89 if it has one but if you have a book check to see if it has crankshaft postion sensor,it might be about to go out.

Im not sure on a 89 if it has one but if you have a book check to see if it has crankshaft postion sensor,it might be about to go out.

No, not equipped with that. I think the problem is a loose connection somewhere. Played with the truck (hand checking all wires and connections and wire routing) and drove it all day yesterday without any problems. Thats the problem with intermitten problems....can't do a thing until it happens.

you didn't say if the outside temp made a difference or not.
I had a 1988 with the 4.9l and the fan for the fuel injectors quit working and when it got above 90 outside it would shut down until it cooled off but when you checked fuel press it was ok
I also had this happen on my 1989 this summer and the fan had quit working but it ended up being the starter selinoid (sorry about the spelling) was going bad

I had an '87 300 6 cyl that did the same thing a few times. Eventually it shut down, never to start again. The TFI module was bad.