Hi there...our car, you may have read, has been exhibiting poor and unpredictable driveability for several months now. Typically lack of power at speed and stumbling/hesitation at speed. I recently replaced the main fuel pump but now a problem has either cropped up with the AMM or the AMM has finally reached its long and drawn out demise?? The car stalled on my wife today following a pop or backfire of some sort. It would start but quit immediately upon releasing the ignition key back to the run position. I got home from work and tried again..same thing. I unplugged the AMM and then the car started and idled no problem. Of course this is the limp home mode so there is only enough power to do this at "parade" speed. Once home I plugged the AMM back in again and tried again...no luck once more. If its unplugged it starts just fine. I tested the AMM as outlined in Haynes, resistance should have been 3.5 to 4 ohms across terminals 2 and 3 but instead the resistance reads zero!! Is this a failed AMM for sure? Do you think the AMM failed and caused the car to backfire or could the backfire have been out through the intake manifold in turn killing the AMM?? Please help...I really would like to avoid the $500 for a new AMM unless this is the real problem??

Thanks