Hello All,
I just made a 4 hour trip pulling our 10,000lb 5th wheel camper for the first time with my new (well, new to me anyway) truck and we had some problems;

It's a 2003 F350 King Ranch CC w/6.0 PSD auto. The truck was pulling great then we stopped for fuel. About 15 minutes later while cruising along the interstate the truck became very low on power and while climbing hills, I could only go about 50mph and even on flat ground with the pedal to the floor it would only get to about 65mph max. The check engine light never came on and I didn't see any smoke. At first, I thought I may have gotten some bad fuel but then we stopped at a rest stop and shut the truck off. When I restarted it and drove off, the truck was back to normal. This lasted for about 45 miles when all of a sudden, the power just fell off drastically again while climbing a hill. I pulled over and shut off the truck and restarted it. It was back to normal again and drove fine the rest of the way.

I noticed a lack of any turbo noise whenever the power was low so I think I'm loosing boost for some reason but why would it come back when shutting off the truck for only a matter of seconds??? I don't have a boost gauge to know for sure. Could it be a sensor on the turbo or wastegate even though it didn't throw the SEL on? Am I looking at a new turbo? I'm out of town on vacation for the entire week so I can't take it to the dealer right now but if it's a simple sensor, I can change it here at the campground (I'm on WiFi internet right now). There's a Ford dealer nearby and the truck is under warranty.

Thanks for any help!

 

Have you checked the air cleaner?

 

Yes, I did check the air cleaner. It looks clear. The indicator showed no restriction. I thought at first that it may have sucked some debris up in it but I didn't see any and I wouldn't think that would explain why shutting it off would fix the problem temporarily.