C10 5.3 Swap Intermittent starting problem (backfire through exhaust)

[240Chris]

Currently have a 5.3/4l60e combo in a 71 C10. Truck has Texas speed cam (no exact info available) and tuned for cam, EGR, VATS, Secondary 02s deleted. E59 PCM, vinned from 03 Silverado on a 2005 engine set. engine set is drive by wire with included pedal and control module. Operating system 12579405. Truck has done fine for roughly 2-3 weeks then randomly didn't bust off the first time I keyed it. rather turned over, popped through the exhaust, release starter, keyed again and fired up without hesitation. Problem occurred completely randomly twice more, and threw P0342, checked cam sensor and sure enough failed. replaced with ACDelco and while removing found typical factory frayed harness on pigtail so cut back a few inches and replaced (Soldered and double checked connections) the pigtail. It has now progressed into a common issue on startup. Every 10 attempts or so we have the starting problem, but not specific condition repeatable. I have completed the cam correlation sync through HPT, fuel cut at 4k functioned and no faults so I assume it took. I have also gone ahead and replaced the crank sensor to be safe. Checked for debris on cam and crank sensors and found absolutely nothing suspect. I have Verified voltage, ground, cleaned all grounds and added extras (Currently 00 from engine to battery to frame in 2 locations. 10g added to each factory harness ground location tied into chassis to battery stud and checked resistance everywhere for good measure.) Checked that each leg on both sensors is same voltage/signal at pcm and checked pins for corrosion as well. I have checked fuel pressure and even attempted to bleed off pressure to see if the fuel system was causing any kind of lean condition causing the no start and cannot identify any effects (clean starts every time.)

Has anyone had any kind of a similar issue with zero faults or DTCs?
Does anyone know of a particular sensor that can cause startup issues without possibly throwing a fault?
***added question. what is minimum voltage for injectors to fire or CKP,CMP, sensors to read (looking into voltage drop while starting possibly occurring through included with harness relay box)***

****Edit note. Took this PCM, flashed co-workers tune into it, put in their vehicle and no start problems there for 20+ startups****

Attached are my current tune, a log file of keying over with no start, simply releasing from start, and keying again and starting fine.

Current Tune
8-16-19 Tune.hpt
Key over, no start, release start, fires up
Startup, keyed over, let off, fired.hpl
Starts fine
Startup Log 1.hpl