This past Friday I took the family out on a horseback riding trip and was loaded down pretty good. about 28,000 pounds in total. It was the first time for me pulling the horse trailer and having the camper on at the same time in that truck. Anyway, We went through a canyon and It really pulled that better than I expected. I downshifted to 4th at the start of the downhill and kept it about 60 then at the bottom I floored it and held 65 all the way to the top.
After I got back in 5th past the top it felt like I was having to push the accelerator down more but I didn't think much of it. Then we came to a stop light in a town and it really felt sluggish then. I saw a Napa down the road and pulled in to get a fuel filter. I swapped that out and checked the screen. It was still clean. It felt a little better after the filter swap but not back to normal completely.

On the way back from our trip I had a 50+ mph headwind most of the way home and it spent most of the trip floored. I was holding 60 and didn't think that was all it really had.

The next morning it ran great again. I took my wife to work in it and it just ran perfect till I went back to pick her up in the afternoon. It started feeling sluggish again.

I am suspecting the turbo binding when the engine is getting warmed up good because I can't hear it at all when it is acting up. Today I put a boost gauge on it and I took it out on the highway to see what it would do boost wise. It got about 17 floored in 4th at about 3000 rpm and up. I'll watch it next time it acts up to see if that is it but I doubt it is.

Does anyone else have an idea what could cause this only when it's warmed up good and even then only sometimes?

Oh, I almost forgot, I got 10.5 MPG on that trip with the slide in and the horse trailer. 28,000 pounds gross. I was pretty impressed with that. All my friends with new Fords barely get that empty.

I almost forgot. This happened to my 94 powerstroke.

 

I'm gonna vote electrical. WAG though.

 

Another WAG .. oil could be foaming (aerating) ?

 

I thought about the oil foaming too but it's a recent oil change on it. About 1300 miles and I used Rotella synthetic. I shouldn't be having problems with that oil already should I?

I'll check out all the connectors under the valve covers tomorrow. I was going to replace one of the connectors connecting to the gasket already and do the O rings too. Hopefully I'll find something in there.