2001 dodge cummins I'll be on the highway and lay on my throttle and it'll boost to 10-15 psi and gradually climb from there.... But if I gradually decrease throttle pressure I can feel my power increasing significantly... Like 20-30 psi total. Fass 150 smarty and TST power max

Any trouble codes? What is your exact fuel pressure when this is all happening? It also could be the APPS going on you but we will need the codes to verify the issues.

No codes at all

I need to get a fpp gauge that's the only one I don't have, lol but it runs like a top otherwise I can turn both my programmers up and get on it and it raps like a new truck it's just on the highway rolling into it I have issues

I think I would do an apps reset and see if that fixes your problem.

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/26-engine-systems/258-how-to-reset-calibrate-apps-sensor

Did apps reset. No fix got a new apps element and it works

Cool

Glad yoo were able to get it figured out. Not very many APPS goes out without throwing codes. Mine did and it was a little hard to figure out at first.

It was weird honestly thought it was my ECM or something deeper than that lol