Have a 2007 5.9 with a six speed. I was on my way back from charleston, wv and was pulling a hill right after i just filled up. I was getting on the interstate going uphill and i was in 5th gear about 2400 rpms and its like my truck hit a govenor the truck would not go anywhere so i shifted down to fourth and got going again. When the truck hits about 2400-2600 rpms in 4th, 5th, and 6th gear its like there is a govenor on the truck and the rpms wont go any higher unless i let off the pedal and get back into it and it usually will do it again. Anybody have any ideas on what it could be??????

 

Fuel filter?

 

Yeap, fuel filter or Air filter. One of the two.

 

I'd be looking at the fuel and air, and make sure your lift pump is working. Just kick the key on and listen.

Check for codes. You might have to turn the key 4 times...

https://www.dieseltruckresource.com/...s-t224833.html