About 6-8 months ago I had a FASS HPFP installed (stock LP was dying). Ever since, the rpm surges slightly when truck is first started up (never happened prior); it goes away in minutes. Truck always starts right up and fuel pressure is good (14-16 psi); mileage is 17-18 mpg; no smoke at startup most times. Never thought much about the rpm surging but recently I had dead pedal 3 or 4 times (push on pedal, no go; let off and push again and it goes). No codes (checked by scangauge, key on/off/etc test, also had a diesel shop check with their scanner). Is the surging indicating a problem that I need to address? Thanks for any help.

 

Some VPs die without giving codes.

 

That is my biggest concern. I took it to a diesel shop that replaces a couple of vp44s a week. They scanned for codes (said you couldn't always get Cummins codes through the OBDII port) but found none. They said since the truck is still getting good mileage, without hard starts / smoking, I am probably OK to continue driving it for now, and thought it might be the APPS (though they weren't sure). I am not so sure about that...

 

I am kind of in the same boat as you. The truck was hard to start hot once back last winter and has dead pedaled twice in the last month but its hard to say since the tank was low at that time also. My truck has surged slightly when really cold in the winter but it has done it the past 30,000 miles I have drove the truck. I think I will run it until it stops going/running really badly.