Kicking this back up top with some new info.
So I went ahead and reassembled everything with the new VC gasket/harness but minus the valve cover, thinking that maybe the short remained due to a condition created by the ECM and the still present DTC code so I intended to erase the code and check a few more things while I'm under the hood.
With all the wires hooked back up, I measured all the low side circuits to each other at the injector and the 3 in bank one are shorted together and the 3 in bank 2 are shorted together, which is really interesting since I have not received a bank 2 DTC.
So then I rescanned the codes, still only P2146, and I wiped it clear. I rechecked all the low side circuits and they were still shorted together within their banks. I started the truck up and let her idle for about 10 minutes. It sounds like something is not quite right, but I can't tell what it is. After idling for a while, no code popped up so I figured it was time for a test drive. I shut her down for a few minutes to put the valve cover back on and clean up my driveway, then I took a spin around the block and BAM, code pops again.
The code seems to pop when I come off the throttle and start coasting, but not the first time I do it. In my drive way I revved the engine to try and pop it, no dice. On the road I accelerated and backed off a few times before the code popped back up.
So now I am wondering if there is any additional test I can run on the injectors while they are in the truck to check for possibly a stuck or faulty one, or would that even cause a short? I have re-ohm'd all the injectors and they are still between .4 and .6, is there any reason to measure voltage or resistance across the injector terminals while the engine is running? Also, is there something to be said for the fact that bank 2 is exhibiting the same condition as bank 1 but there is no code for bank 2?
I will appreciate any ideas and thoughts here guys, I feel like I'm just grasping at strings now.