Well to get boost you need fuel if you lack the fuel then no boost? have you replaced the map sensor at all? it what controls how much fuel the Inj Pump delivers and the boost...

Alright so I am gonna replace the map sensor. I took the chip out and have codes- P0237, P0253, and P0382. The 253 code kinda scares me because it has the words "injection pump" in the code readout. :argh: I hoping getting the map sensor will make the other scary codes go away. I just put this IP in like 5k miles ago and never seen pressure drop below 11 PSI EVER.

Na, Ive seen the map sensor throw an Injection pump code, change it out and see what happens..

fix the check engine light and that should fix your problem

I am wondering where i can buy a map sensor? Local garage dont think they can get it and closest Cummins garage is over an hour and a half away and i cant find there new number :scare2:

Napa, or autozone, or orileyrs auto parts will have it...