Ok so i replaced the vp44 and bleed everything but my truck idles so rough it sounds like its about to die. I have no clue what is wrong with it. i made sure during the vp44 install that everything was installed correctly. what could be the problem? also i installed a fuel pressure gauge. when i start my truck it sits at around 11 then when i drive it sits at 9-10. but if i let it idle for say 10 mins. it drops to 0. it won't climb back up either when i start to drive it stays at 0.

 

low pressure pump, maybe. when mine went, it would hold 6-10psi at idle then randomly die and come back. is it the original lp pump, any codes.

 

no its the bd pump. 100 gph. it said bad map sensor. but would that really make it idle that rough?

 

sounds like time for a new pump and map sensor!