Engine/Transmission (1998.5 - 2002) Surging...is this the APPS???

[jzenk]

My '01 2500 HO has a funny "surge" lately. More like unsmooth acceleration. It's most noticable when the engine is cold, and not so bad once it warms up. Doesn't go away altogether, though. It's worst when taking off from a stop and seems worse on really wet / humid days. I don't notice it under hard acceleration or with the cruise on. It's got 120,000 on it now. Only mods are a FASS system and AFE intake. VP replaced at 45,000. 6 speed. This isn't the "dead pedal"... I've been there. The hesitations are very short. But instead of smoothly gaining rpm, it kind of "steps" up to rpm. Turbo boost is normal always and I've checked the tubes and boots. I haven't checked injectors yet. Curious if the go fast pedal just isn't sure where it is (APPS) I've cleaned and greased the connector on the pump and everything looked good there. Oh yea, no codes either. Am I thinking right? APPS, sensor or injector(s)??? Any help will be appreciated. Thanks guys!!! Jim

 

[gregdoerfler]

i had what seems to be the thing happen to me, it started out just slightly just enough to notice it then 3 years later it got real bad, i thought it was the vp going out but i recalabrated it by taking the voltage reading and turning the apps and it fixed, there are instructions on here just look for recalabrating apps or tps im not sure you should find it.

 

[PC12Driver]

Before you spend the time reclocking the apps, you might want to read this. The popular idea around here for "recalibrating" the apps will only affect autos.



I'd vote for the APPS in your case. Especially since you said that it goes away when on cruise, since the APPS is bypassed with cruise engaged. Here's an earlier thread about the APPS surge.