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.
The engine will start and idle normally for 20 seconds. Everytime at 20 seconds, P1514 sets and the engine stalls. REP illuminates.
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 and glitches.

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

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

Thanks!

 

Just an FYI:
KOER - key on engine running
KOEO - key on engine off

The next step for me is buying some 2nd hand known good parts to swap. I just want to see what else has been done successfully.

 

Try pulling on the yellow and brown wires near the throttle body. Often times the wires become brittle, and will break there causing a code.

 

Thanks for the feedback. I have checked the terminals at the throttle body. No stretched wires or wallered out female terminals.

Would you guys want to see a snapshot of the TAC data when the code sets?

 

I had issues with my truck a few months ago where I was getting the "reduced engine power" usually on cold start ups. I replaced the Throttle position sensor and pedal sensor with no luck. Turned out my TAC module was being shady, replaced it with one from the salvage yard and haven't had any issues for over 3 months.

 

I found some new feedback that makes me want to dig into the tune more. (I have an EFILIVE on the way)

When I apply throttle with the koeo, the throttle pid APP% goes to 100% at only half pedal travel. I think this is a big part of my who issue. I will work on the scaling once I have the efi on there.
Anyone else run into this?