I'm driving a 1999 F25o V10 Superduty, it has a manual transmission with 4WD.
Around town it behaves wonderfully. Although the mpg tends to bounce between 10 and 13. When I take a road trip, get it out on the highway and set the cruise... bam, about 200 miles out I start losing power like I'm out of fuel or something. Kick it down a gear and rap it and grab 5th gear again and it straitens out for a bit , then does the same thing again then trips the p1151 code. get back in town, no codes, no problems till the next trip to college. Usually I'm pulling grade or a trailer when this happens. lack of HO2S-21 Switch, sensor indicates lean. Can't things just break and stay that way till you can fix 'em???

 

Might be something as simple as a restricted fuel filter.

 

I should have mentioned that i replaced the fuel filter and fuel pump last year hoping to cure my problem. I should say I fixed another intermittent problem and i was hoping the 2 problems were somehow connected. Never know until you hit the road. Been running "sea foam" the last 2 tanks hoping to clean injectors. I can't hear any vacuum leaks, connections all look good. was thinking egr valve or o2 sensor. I was hoping to avoid playing "replacement technician".Limited resources,{did I mention the kid in college}350 miles from home [

 

Made the trip down, loaded with stuff. Pulled a 12' U-haul trailer. Left the truck in 4th gear 2500 rpm 60+ mph going south. The 1151 code tripped again about half way down(150mi.) but the truck ran great. On the way home empty, with the trailer still in tow, I tried 5th gear at 2250 rpm. Ran o.k. for a bit then started to bog down. Had to gear down to forth and mash the gas just to maintain 55mph. Woulda thought I was running out of gas. Stopped and filled the tank, gave it a minutes rest and hit the highway again in 4th @2500rpm 60+. Again, no loss of power the rest of the way. But the mileage was down to single digits, OUCH.