I have been trying to get my '81 ZXT running right for months! Just yesterday I was doing some of the diagnostic work that my new Turbo Supplemental Manual recommended and explained and I discovered a discrepancy with the AFM....specifically the Air Flow Meter resistance was erratic. I had already removed the sealed plastic cap earlier to fiddle with the adjustment in there, so the "rheostat" part was accessible to look at. The problem was that the rotating copper pointer part was not making good contact with the circuit board part as it swung around with movement of the air flap. I found this to be the problem by exerting a little pressure on the needle with my finger as I moved the air flap and saw that the resistance was then OK. I cleaned the circuit board part with lacquer thinner and bent the pointer ever so slightly to increase the pressure it exerts on the circuit board. Voila! No more erratic running! While before it would run rich, then lean, then not at all, now the plugs are golden brown! Amazing! I was getting ready to look for an AMF myself. Suggest you check the resistance at the ECU per the manual as you move the air flap through its range. This can be done with the AFM on the car....just remove the boot from the air cleaner to the AFM and the flap is just inside. Motorsports will rebuild your AFM for around $165 if push comes to shove. Normal 280 ZX owners can buy rebuilt ones off the shelf (exchange), but us Turbo owners have to send ours in for rebuild.