A few days ago I was driving my truck home and I admit I didnt let it warm up and it was about 30 degrees outside. Im running IDP extreme street tune and when I got on the highway it was running fine til WOT then my Fuel perssure gauge dropped to below 10 and the truck felt like it fell on its face then it picked up and was fine. So I chalked it up to being cold still. Then yesterday while at operation temperature the same thing happened when I stood on it the fuel pressure dropped again and I had power loss. Im thinking maybe fuel pump ? I just replaced my fuel filters 3k ago. Any suggestions?

 

It's probably the fuel pressure regulator sticking open. It well could be the HFCM, or the fuel pickup in the tank, there is a diagnostic step by step procedure to follow to find out what it is. I would stay away from WOT till you get it fixed, that feeling of lack of power is actually the sound of you buying new injectors... They will fail very rapidly at 10 psi fuel pressure and trying to run WOT.

Brian