I have searched and found different results and thought I would just tell the whole story and maybe someone can help.
1992 F150 302 engine E4OD tranny all original. 244000 miles Original owner!
Tune up was three years ago but only 7500 miles ago. Plugs,wires rotor and cap etc.
Truck starts easily and runs fine. Smooth idle, lots of power, and no check engine lights or abnormal gauge readings.
After 1 1/2 hours of pretty steady driving at 50-70mph it loses power. Slow to respond to gas pedal. Loses power on hills and backfires through throttle body.
Let it cool down overnight and you are good for another hour or so. Never get a check engine light!
Only code is 332 Insufficient EGR Flow Detected.

I have looked around for obvious things like a lose vacuum hose or something!
I would appreciate any suggestions.

 

I would suspect the ignition module, breaking down when it gets hot. I'd also check for a clogged cat.

 

I agree with glc on the ignition module as a high probability. Especially if it is mounted on the front of the distributor where it gets heated from the air coming through the radiator. It's a common failure. I had that problem on my 86 f150 302.