I've asked about this previously and received some help but the issues are now worse than ever.
I've got a '73 Camaro running an '05 GTO LS2, LS2 Throttle Body and C5 Corvette Pedal, T56, E40 setup that I've been fighting throttle issues on since we put it together. If you turn the key straight from off and start the car the APPs both act normal but the throttle responds slowly and won't go to 88% (WOT on this setup); it may flash there momentarily but it drops down to roughly 40%. If you turn the key, let the ECU run its prime cycle on the fuel pump, turn the key off and THEN start it-it fires right off and the throttle is crisp and perfect. Now I am occasionally dropping throttle control all together where the APP shows normal but I'm not getting any response at the throttle body. When this happens I get a code p2157 and/or p2127 and nothing we regain throttle body control until I clear the codes. I suspect there is something I've missed in the wiring but I can't fathom what. What wires coming into the ECU actually provide the power and ground into the internal TAC module, I suspect that is as good a place as any to recheck.