Engine/Transmission (1998.5 - 2002) missing at idle

[RobertMiller1]

My cummins used to be silky smooth at idle. With automatic trans, in drive at a stop sign, it was impossible to ever detect a stop in the rythm of the engine. I have always been amazed at how smooth it was.



today, I noticed a regular "miss" or stumble. I am afraid this might be a lift pump failing. Anyone else ever have this kind of symptom?



gonna try to get my hands on a fuel pressure guage. I did bump the starter and could hear the pump pumping, actually pumped longer than I thought it would and doubled cadence/frequency, and then it finally quit. I suspect it could be weak at supplying fuel.



Opinions?

 

[Sticks]

Fill out your signature so we can see what all you have... Year, manual or auto, modifications...



I would check for codes first to see if there is anything stored in the computer, fuel pressure, ground connections...

 

[RobertMiller1]

sig

How's this.



btw... it ran perfectly this morning... go figure

 

[RobertMiller1]

sig

sig mod

 

[Turbo Tim 1]

Just so you know, if you go and change your signature it will be changed on all previous posts so you don't have to post a reply to see your new signature. Back 50,000 miles ago my truck got a lope going when idling and warm out, happened for about two weeks, everytime I went to get it checked out it wouldn't do it, then all of a sudden it stopped and hasn't done it since. One mechanic did hear it doing it but as we were checking it out it stopped so it was kind of a guessing game as to what came first the chicken or the egg. Been fine ever since.

 

[RobertMiller1]

Understand that is the theory,



but when i went back and checked it had not changed the sig or applied it yet.



even with a refresh.



There is a time delay for it to update the profile. More so than I thought.



It does work as you say, as most boards do, I was suprised when it did not apply the sig, hence the test.



And as you can see, it has lost it again. twice that has occurred now.



submitted yet a third time. we'll see how long it lasts this time.



Now one of these messages has the sig, 3 others including this one do not.



Must be a Microsoft server :-{}

 

[Sticks]

Your signature only shows up on the (your) first post on each page.



EDIT Now to answer your original question. I was going to say if you have larger injectors, that would cause the funky idle, but all you have is the box. Does anyone know if the box changes the timing at idle, or is it like the Edge where it has to have boost to start the timing advance?

 

[RobertMiller1]

don't have a box. The superchips reprograms the dodge computer. Saves original settings.



And it has been installed about 2 months. 2 months with perfect idle.