stumble...isc

[hookliftpete]

Recently replaced the gear pump and injector pump (rebuilt) on my 2008 pete, with an isc. Previous to the new pumps, the truck had a stumble in the top two gears around the middle of the rpm range. For a couple of days following the pump replacements, the stumble was gone, however its returned. Any suggestions as to what to look at next? No active codes, fuel rail pressure is good, injectors/lines/quill tubes all replaced last spring.

Thanks!

[JimT]

If it only happens in the top 2 gears then maybe look at the transmission? What kind of transmission is in there? Around what rpm does it occur?

[Signature620]

With Insite, monitor a few things like rpm, percent throttle, engine operating state, vehicle speed, rail pressure commanded/measured & see if any of them change as it stumbles.

[hookliftpete]

Is there a way to record that as it’s being monitored? Graphing of some kind?

[Chamberpains]

Insite and c.term both have graphical monitoring capabilities.

[JimT]

Hmm, this is more of a question for others reading this, but could the turbo cause this symptom? Say it's getting stuck at a certain position and is only noticeable in the higher gears where your acceleration is more gradual?