reduced engine power p1514 KOER set at idle but P1518 set KOEO

[megadeus]

The truck is a 2006 gen 3 4.8 1500 silverado.
It is converted to speed density and running on 80 lb/hr injectors.
Yes it has been tuned. By who, I have no fuggin' clue. - I'm thinking about reflashing the pcm to efilive eventually.
The engine will start and idle normally for 20 seconds. Everytime at 20 seconds, P1514 sets and the engine stalls. REP illuminates.

Most of the searches I've found around here have P1514 occuring way up in the RPM range, not at idle like im experiencing.

I can't seem to lock down what changes at 20 seconds to set the REP/P1514.

If I apply throttle at any time before 20 seconds, P1514 sets with a subsequent stall. REP Illuminates.
If i clear codesand turn the key on with the engine off and manually apply throttle, P1518 with REP illuminates.(battery fully charged)

Throttle body harness inspection yielded no broken wires or burnt terminals. I replaced G103 and G104 grounds on the back of the heads.
I did a sweep test of the TPS #1and #2 on a bench with a scope and didnt find any glitches.

I inspected the connections at the TAC module and found no evidence of damage or tampering.

I don't know if this fact is important.. but right now it has a turbo kit on it but the intercooler system is not installed. So when I'm starting it, it's just an open throttle body.

I hate playing parts darts with cars and just posted this info in hope that these kinds of symptoms have been experienced before.

Thanks!