While on my way camping my 1996 F250 7.5l was climbing aome pretty gnarly hills for a long period of time while loaded but not pulling anything. After climbing in elevation for about 2 minutes with the pedal to the medal i started to hear a tick and it started bogging down and losing power. I dropped to 45 mph and got to top of hill. Right away ticking went away and got full power back. It didnt happen again until on the way home on the same long hill from the opposite side. Oil pressure good. Temp good, no lights on.

Any ideas? I cant get it to duplicate the symptoms if not climbing for a few minutes.

 

Sounds like heat related - do you have a proper temp gauge?