I have a 99. The lift pump and VP were changed out less than two years ago.

I have been having a problem with my truck over the last 3-4 days. Driving at highway speeds there is a quick miss and then no power. I can not accelerate at all. When it has happened I have down shifted and once things were normal again and the second time it happened it did not fix the problem but when I shifted back into 5th gear the problem was gone.

Any ideas on what the problem might be?

 

Could be the APPS, MAP sensor, or even something in your fuel tank starving/blocking the lines (I've had the latter two do close to what your describing).

 

After reading the troubleshooting steps on bluechip diesel it is the VP. Second one in as many years.

 

You need to put in a new lift pump before replacing VP. Go aftermarket m maybe a FASS or Raptor. I bought a truck with a fresh VP and a new lift pump, OEM. the lift pump put out 3PSI. That is what killed the VP. I took out perfectly good OEM pump and put in a FASS pump with out the air eliminator and now I have 16 psi and don't worry about the VP.

 

Yeah Whiskers that is the plan. FASS DDRP lift pump and a Blue Chip VP with a new computer.