My LS3 is experiencing a wiring fault somewhere in the circuit which is affecting the GM E67 ECM in strange ways. ECM was swapped as I have spares but same issue.

The engine block has less than a couple of Ohms and only a .2V drop from battery terminal to block, so it's solid. I'm getting up to 85-100 Ohms on the ignition circuit and went through all normal elimination steps to trace fault without luck. The harness does not seem to be the issue as there are no ground faults detected on any leads with all sensors/loads and ECM disconnected and while wiggling.

Performed all the normal methods to trace the fault but still coming up empty and running out of ideas. Hoping for any recommendations for a guru in the Colorado Springs area for help and happy to pay for their time.

I'll also try posting in regional forum. Please PM me if you have a recommendation in the area.