1996 vortec 5.7 tps fault

Ok, here is a difficult one. I have a 96 GMC with a 5.7 Vortec and have a temperature related problem. In Texas it is only cold for four or five months out of the year. When this time comes around I get a high eratic idle and DTC P0122, and P1122. TPS circuit low input and intermittent low voltage. I have rebuilt most of the truck and replaced most sensors after 150,000. TPS, Coolant, IAT, IAC, and infamous EGR 2 times. I have checked connectors and wire resistance of the TPS circuit and found nothing wrong. My next thought is a bad VCM. I hate being a parts changer but I no longer work for GMC and have no access to Advanced Scan tool commands. Any advanced techs agree with my findings or have other suggestions?