error code, loopy idle, cutout test thoughts

[Rounded_nut]

2014 CM2350, PukeDits cam and turbo, PukeDits program replaced by well known cool guy on forum.

Error Code 3338
Engine idle fuel quantity - data below normal operating range - severe level
4 counts
Inactive

So I've been having an issue where the idle will sometimes get lopey or rough, in other words just not right, and this occurs at low and high idle. I did the cutout test monitoring pressure, rpm, actuator, and got nothing that screamed I'm the bad injector. I cut out all but one, pretty similar results. So I cut out the front 3, then the rear 3; difference! Front seemed to have an easier time normalizing idle compared to rear. Quickserve only gives one possible cause, malfunctioning injectors. From what I can see on the parts diagram, the main injector harness comes in and splits off to the injectors, so is it even possible that the error could be related to a poor connection to the rear set? I would think not, that the offending injector would make itself known, and perhaps a finer ear could tell but I cannot. Is there another parameter I should be monitoring that does a better job of pointing fingers?

I have rebuilt the fuel pump head and replaced the lift pump and actuator and replaced relief valve, all less than 100k miles prior, #6 injector replaced with cummins reman appx 120k miles prior, injector harness to my knowledge is original, injectors 2-5 are factory, currently 894k miles, all fuel lines from tanks to left pump are original, #1 & 6 injector supply tubes and lines replaced at time of new injector, fuel pressure leakdown show 6k PSI loss in 30 seconds, currently 20 minutes since shutdown and pressure is nill, if it's relevant the data with engine off goes -33 to 18, not sure why, could it be a faulty pressure sensor contributing to erroneous calculations as to what the idle fuel quantity should be?

I'm selling the truck shortly and while I have no desire to sell a truck with issues (aside from ravenous fuel appetite), I also hate to drop close to 4k on injectors!


Am I completely missing the source or ?