A guy dropped off his truck for my buddy to look at. He said the symptoms were when the truck was cold and you start it, it wont rev past 1200 rpms. He said if you turn it off and restart it, all is well. The only code that came up was a companion code. My buddy also said that when he had it running this afternoon and you would rev it up past 1200 it sounded like it was missing, deff was not smooth. Niether of us have any idea what the fuel pressure is yet. Fuel filter was changed not to long ago. Any ideas would be great, thanks.

 

I wouldn't start it again until the lift pump fuel pressure has been determined to be at least 10psi on the starter bump....turning the keyswitch just enough to "bump" the starter then quickly release/The Free 25 Second Lift Pump Run.
A fuel pressure test kit that'll fit ours (and GM gasser stuff) is available at most chain type auto parts stores...pic in my Gallery.

 

a little more info on whats going on. My buddy drove the truck around this morning. He said that the truck was getting a serious dead pedal and would go over 25 MPH with it held to the floor. He drove it around for a little bit untill the truck came up to tempature. He shut it down, then restarted it and it was fine with no dead pedal at all. We are going to try a APPS reset on it and test the fuel pressure. From what my buddy told me and what the owner told him, these symptoms are only present when the truck is cold. Thanks for the help

 

I would check the codes 1 more time . it sounds like a vp electronics issue Vps can fail with out setting a code but most of the time it will. start with fuel pressure test then you could try the apps