My 99 3500 lost boost coming home the other day. No lights came on and after about 20 minutes it came back to life and ran great the rest of the way home. Now when I start it up and take off, it has no boost in the beginnning but will gradually build up to around 10-11lbs as the truck warms up. From there it's anybody's guess as to how it will act. Going from nothing to full power again. It starts great and has yet to throw a light. I just took it to our local Napa and had them plug it in to pull the codes and it showed nothing at all. Not even in the "Stored" side. I did try the APPS reset and that seemed to make no difference. It's showing 10-11lbs fuel pressure at idle and will pull down to around 6-7 at WOT pulling 6K. My question is: why are there no codes thrown? What should my next move be? Could weak fuel pump cause this type of problem? Any and all suggestions are greatly appreciated.

Fuel pressure way too low... Book standard is 10 PSI as a minimum and I'm suggesting of keeping 14 PSI fo long life. But it could be the injection pump is internally damaged and can't produce the fuel required for the truck. As for fuel pressure I run now 18 at idle and 16 at WOT with 15,000# GCW truck and trailer.

Where would you go from here? Install new LP and larger lines? Or go ahead with new IP & LP? I need a plan of attack. At what point would I normally see it start to throw codes?

The APPS could be bad too. I wish there was a way to tell which one was causing you a problem.

AirDog, FASS or Raptor... They are complete kits with plumbing, electrical, fittings, etc. Also come with a lifetime warranty. Just don't do a stock replacement pump or a FASS DDRP (Dodge Direct Replacement Pump). These are junk because they don't deal with the plumbing, locations, or increase flow. But I question the life of the injection pump still being the fuel pressure is way too low... Fuel pressure is exactly like oil pressure. A engine will run with low oil pressure but how long till there is bearing damage? Same thing with a VP44 the fuel is the lubricant and if the fuel pressure is low how long till the VP44 is damaged? Truth is some get lucky and some don't...