I have a 3rd gen 91 Z28 5.0 L installed in the rear of my Fiero. ECM is the 7730. So I decided to check the TPS voltage via AUP1 and a power probe. Key-on-eng-off, bat shows 12.7v, ALDL pins "E: & "M" (org wire) show 12.7v, C203 pin "B" show `12.7v, but the voltage showing in TunerPro's dash shows 12.2v. That's 0.5v difference. Call me ****, but can anyone tell me why? Thanks in advance as always.

 

Voltage drops though the connectors, wires, and ignition switch.

RBob.