My tuner, Airboy, was concerned because everywhere in the engine bay that I measured, the voltage was steady, however the ECU was seeing varying voltage. He pulled the ECU out and started testing wires. Sure enough, all the ECU grounds had an extremely high resistance (4+ohms). Something was wrong with the grounds. I called Brian at iWire who did my wiring merge and he said that all the ECU grounds terminate at the Intake Manifold.
Fast forward a few minutes to this bolt:
, on Flickr
Somewhere along the line, this bolt was undone and not tightened back up which meant that the ECU wasn't grounded properly. Sunny cleaned up the grounds and the grounding point and tightened the bolt. Started the car... ECU is seeing steady voltage. Better than that, the Idle was normal. Better than that, no misfires when we revved the motor up.
The car is now ready to be tuned whenever Airboy has an opening. We did a couple of pulls, turbo should make full boost by around 4200rpm-ish (yay Altitude!). Once you get up there, it feels pretty damn powerful... but thats compared to me limping the car around with misfires and an unhappy ECU.
Huge thanks to Airboy... amazing work as always.