03 6.0 2500hd: Reduced engine power, at my wits end

[Terinass_sydwayz]

I have been trying to track down the source and fix REP since I bought this truck about a month ago. 

Codes observed are:

P1516 TAC issue

P0220 throttle B circuit

P2135 Throttle pedal a/b mismatched 

 

I have tried the 3 min running 30 secs off 3 min running relearn and the REP pops Everytime on the 2nd 3 minute mark. It will run like trash, if you shut it off for about 15-20 seconds CEL will be on but seems to intermittently run ok before the code comes back.

It seems to be a wiring, TAC, or PCM issue to me. 

I've about done about everything I can on it.

I did buy a big scan tool and will experiment with it later tonight, but I'm really uneducated on how to monitor it or reset and relearn the right data with this Autel MaxiCOM MK808BT PRO Scanner I purchased hoping to solve this.

Here are the things I've done to troubleshoot this problem:

 

TPS, TAC, APP wires greased

PCM1 10a fuse replacement

Pass engine block ground cleaned, recrimped, greased, added ground

Drivers engine block cleaned, recrimped, added ground

Hood to firewall ground added

Block main ground cleaned, greased and reattached

Alternator charging wire larger gauge new wire

PCM checked, no burnt pins, gasket is pinched and could have let moisture in, but everything looks good otherwise

TB replaced

TPS new pigtail soldered in

2 different TAC modules from the junkyard swapped in with same similar results

1 APP pedal swapped in from the junk yard with matching TAC and wiring harness.

 

Any guidance or help is appreciated greatly. Need a next step to follow 

[davester]

charm.li will have vehicle-specific diagnostic procedures for the codes

work the codes from lowest number up, one at a time.

 

[asilverblazer]

Looks like you need to check the wiring - check resistance/continuity between point a to point b. Look for obvious problems frayed or pinched wires.