2013 Chevy Silverado 1500 - No RPM on Dash (period) or Scan Tool (kind of)

Vehicle:  2013 Chevy Silverado, (4-door), 4x4 Z71, 5.3L
Issue:  Long Crank time to start, No RPM on dash, misfires on cylinders 3 & 8.

Figured I would tackle the No RPM & long crank time 1st then worry about the misfires (coils are not firing (swapped with known good coils (off my truck) same result - also did compression test both cylinders were just under 160psi, and both cylinders fuel injectors were (at least) being commanded to fire (noid light test)...)

Came to me after a new AC delco Starter, Crank and Cam sensor had been installed and a new harness for the cam sensor (looks as if it had a front seal replacement as cover is new too).
I didn't get a lot of time with the vehicle as of yet (do diag work on weekends) but what I have done so far is verified no blown fuses anywhere (actually had one for trailer brake systems but I replaced it).  put the scan tool (autel) on the vehicle and in most every engine menu for RPM I get NO reading, BUT if I drill down in the ignition sub menu to the crank sensor itself I get an RPM reading, so crank is supplying a reading to the PCM.

Next I verified the wiring and terminals/pins from the cranks sensor to the PCM - no issue there.  I then did the same thing for the Cam sensor (new harnesses always make me suspicious) - all good there as well, pins/terminals good, no corrosion or looseness, good continuity - could light test light (incandescent bulb) through the each wire.  (crank & cam wiring all goes to the X2 connector).  Next I pulled the fuse block out and checked all terminals/sockets on the back of it for corrosion, burnt/bent pins etc....none found - all looked good.

Things I also verified with the scan tool:  (according to the scan tool) no issues with the 5V Ref-1 or 5V Ref-2 circuits (reading 5V on both so no obvious short to ground or power issue.).

I know the PCM sends an RPM signal to the Instrument Cluster, but does the DLC get it's RPM data via the cluster module.... I guess I need to find/read the entire description/operation of both the crank and cam circuits.  I did find in a forum thread where someone had mentioned that the crank provides timing for cylinder #1 and the cam provides it for cylinder's 2-8 but couldn't verify that (again haven't read complete D/O yet).

Anyway...just wondering if anyone had any things they had ran across that I could be on the lookout for.  I will update more/outcome whenever I get it figured out/repaired.

lets first make sure we have a fully charged battery.

let's also make sure we understand the unique design of the ignition system.

-ignition control module

- pcm

sometimes vehicles have pcms that has an integrated ignition module and does it all.

what's our inputs during long cranks?

we cannot have fuel and spark if the vehicle is struggling to start.

do we have fuel, or spark?

how's our ckp circuit and our cam circuit?

is our starter weak?

The ckp sensor also depends on the starter at the beginning to aid in generating a signal.

weak starter = weak signal.

@kazooie, How about you stay out of my thread with you condescending attitude/useless questions/statements that were mostly already answered in my original post and I'll promise to not comment in your threads with your own condescending comments right back at you anymore. Deal?

I didn't read any comments as condescending but regardless, let's continue:
I would attack the 2 cylinders with no spark first. You have something tangible right in front of you. See where it leads you, then go from there.
Long crank times can be caused by a lot of different things, with fuel pressure bleed down being the main culprit.
Scan data RPM or cluster RPM is a guide only and cannot be relied on as a 100% fool proof test.
I bet if you attack your 2 cylinders with no spark, this will lead you to the promise land

Ok I'll change gears and attack the two dead cylinders first. Thank you Sir, And I'll try to calm down a little too

Sorry kazooie

all good, Im confident you'll fix the issue. take your time doing accurate tests unlike me lol