Ok so finally got a spare stock motor in while the other one is built, but the pos won't run.

Can't rev past about 2500-3000, it just stutters and cuts out. Feels like ECU is in safe mode. I got plenty of spares so I've changed the AFM, I've changed ECU, I've changed the TPS, i've looked everywhere for vacuum leaks... I can't think of anything else??? I'm ready to light the car on fire!

Anyone have any ideas?

What should the voltage readings be across the AFM wires? I might try add a direct ground to the cable, but can't remember which wire is which.