45 seconds of confusion...

[Smokin64]

Hey guys, I'm new so it's story time, trying to diagnose an '06 ISX 475, CM870, 1.3M miles total, this engine will start, no questions asked, every time you hit the key, doesn't matter if it sits 10 minutes or 10 days, it starts. However, every single time it starts, hot or cold, it has a BAD misfire, sounds like a "B" John Deere for about 10 seconds, then it's like it gets one cylinder back and sounds better, then another, and within about 45 seconds of starting, it smooths out and idles normally. Then you can drive the truck with no issues, full power, no smoke, etc.
-Note 1: ABSOLUTELY no codes at all, unless it misfires long enough to throw a "cylinder unbalanced" fault, (thanks Captain Obvious).
-Note 2: Injectors and o-rings were replaced about 4k miles ago due to 25.3% fuel dilution. Turns out the cylinder head had a crack at the upper fuel port for injector #3, and at 25% fuel dilution and 600k miles since the last overhaul, it got overhauled again. This rough idle starting issue began about 1 week after the overhaul, but I have no more fuel in the oil.
-Note 3: The injectors are from Delphi, not Cummins. (not my choice)
-Note 4: Injector cutout test shows no problems, I can hear every cylinder no matter what RPM. However I do not have Insite so I can only cut out one at a time. (not my choice)
-Note 5: Cylinder performance test shows all are working correctly
-Note 6: Metering and Timing solenoids have already been replaced because someone told the owner that they were bad. I would have tested them and taken them apart, but that wasn't my call to make.
-Note 7: This truck was deleted by {THE HORRIBLE PLACE IN uTAH} at about 550k miles, dropped a valve and got overhauled at 770k miles, and then the fuel dilution overhaul at 1.3M miles.
My thoughts: probably not an electrical or sensor issue since I don't have any codes, and probably not a fuel pressure issue since the truck runs great after the miss clears up. I've tried for 3 weeks now to find a test ECM, can't find one near eastern Iowa. I watched Rawze's video and ordered the injector bubble tester kit today, maybe that will show something. Has anyone heard of anything like this before? Sorry for the rambling..