I cannot produce over 15lbs of boost or if try to go full throttle the truck starts missing and loses power and boost dops to zero, no smoke, i am thinking lift pump!?!?!?!?!? fuel filter changed at a 1000 miles ago, and there is a general loss of power overall!! truck idels great, about a 100 to 200 rpm slower, but starts every time but just dont build boost!! no high end power and when hit hills, feels like my old IDI 6.9 Ford with a bad miss though!! Any insight would be great!! This sight solves my issues everytime!!!

Thanks,
Mike

 

A simple way to test for a bad lift pump is by replacing the fuel filter. The first time I replaced it I filled the filter but there is always a little air, I started the truck and brought the idle to about 1000 and it died once it got the air. I had a bad lift pump and it took running on ether for ahwile while cracking fuel lines until the pump primed. Some guys will tell you a p7100 won't run with a bad lift pump but it will. Even with a bad lift pump my truck would start on the first crank with slight throttle. The only issue I had was power and fuel filter replacement

 

Thank You!!!! It is a bad lift pump!!! You are right on the money and again thank you SOOOO MUCH!!!!