91 5.7 TPI/Auto

I've been fighting with a code 43 for two days and can't seem to find a clear diagnosis. Using a Chiltons manual, a code flow chart from Mitchell, and a TECH 1. I'm thinking it's an electrical problem, but have not ruled out the fact that it might be in need of a custom calibration.

The car has:
- a stock ECM and PROM
-Comp cam (prior owner is looking for the cam info)
-roller rockers (not sure what ratio yet)
-TPIS big mouth lower and runners
-BBK 58mm TB
-MSD coil
-headers with some muffler shop y-pipe to a flowmaster


So far, the one thing I can't verify (normal or not) is why I have battery voltage at the knock sensor connector with the key on (not running). 0.00 volts key off. Both diag flow charts I'm using say it should be about 5 volts. I have traced the wire from the knock connector to the ECM looking for a short to another wire - nothing.

When it happens:
-still in open loop
-coolant temp up to 120-160
-idle surges from 1600 - 500 RPM
-knock shows up to 8* during the surging
-runs crazy RICH- it's eye watering

I'm hoping some of you TPI guys can share some of your experience with this Code 43. Maybe something else I need to check or do. I have not replaced anything yet and the prior owner has replaced the ECM with a reman unit.

Any ideas would be great!

ST