1991 F150 4.9L
I'm having similar problems.
It starts up from cold and runs, drives.
Seems just fine.
When warm(er), it stalls, sometimes intermittently, sometimes immediately after starting, and very rarely it will run for 10-20 seconds with normal power/etc.
Replaced cap, rotor, wires, coil.
Still doing the same thing.
Tried switching fuel tanks, no change.
Montana_1, if you find a fix please post; your email is disabled, so I can't email you directly.
I'm going to mess with the IAC next.
For the past couple of years it's had an occasional intermittent miss at idle, but didn't seem to affect drivability, figured it was the original ignition components. Still does it after the above ignition part replacements.
On rare occasion it would misfire/stumble while freeway driving. Since it's not staying running, I can't check that now after the ignition parts change. When changing the wires I found that #5 and #6 plugs were loose, the service tech probably had finger-tighted them then forgot to torque them. That was a couple years ago!
I've found other messages that mention TPS, PIP module in distributor, fuel pump pressure low (but I switched tanks, so doubt that), and a short in the PWC but only 93-95 listed (see http://auto.consumerguide.com/auto/u...ex.cfm/id/2035