Alright guys, I'm completely stumped by this and need some help figuring it out...

I replaced the intake manifold recently on my 1995 K1500 and everything went back together fine, BUT my injectors are not firing and I cannot connect to the PCM nor can I pull codes via the paperclip trick...no idea if these separate issues are related at all.
I swapped out ignition modules since I had an extra module laying around and no luck. I also pulled the dizzy and installed a new AC Delco pickup coil and turned the distributor with a drill while I checked coil output with a multimeter to make sure it was working properly, all good there and still the injectors refused to fire.
I checked both ecm fuses in the underhood fuse block...the fuses are good.
I checked all PCM grounds for continuity...grounds are good.
I jumped the injectors with 12v and the injectors are functioning properly.
I swapped in another PCM and still no luck(this is NOT a known good PCM).
I checked input voltage at the PCM with key on and am getting good voltage to the PCM.
Thinking that maybe my chip got smoked somehow, I burned a brand new chip and...nothing.
I've checked and rechecked that all sensors are properly connected.
Fuel pressure is good and pump primes as it should with key on.

I did swap to a 454 throttle body and rewired the IAC and TPS while I was doing the intake. I just matched wire colors when wiring in the flat TPS connector...did I wire it wrong maybe? I did unplug the TPS connector and tried to fire it just in case that was the issue and still no luck.

Perhaps I should test this TPS for proper function...I'm grasping at straws here though. What did I screw up?? The truck ran before I tore it apart, although I was experiencing a strange high/hanging idle and I think this issue happened before I replaced the intake because the truck wouldn't start the last couple times I tried to fire it up before removing the intake.

Thoughts?