Don't want to hijack this thread, but perhaps my problem may be same of related. My car is a 280zx NA, 1981. Tell me if I need to create a new thread. Engine keeps running , sometimes, not always, after I turn key key from On back to either Acc or Off. Sometimes the engine just keeps running, I can remove the key, but when I put the key back in and turn to On engine will stop. Could there such a thing as a sticky ignition switch? Never had this problem until I installed a MSD box. Engine starts and runs fine, it is just the turning off that is a problem now. MSD technician says I must try install a diode on the Lamp light wire coming from the alternator to regulate the flow of current. That to me would make sense if there was just a slight charge left in the system enough to trigger the ECU and SMD box. Initially the engine would run-on only when key in Acc position, and about for a minute or so (I guess till it runs out of fuel), but now since yesterday it would just keep running even if key is removed from ignition. That indicates to me that the fuel pump, alt, ecu, msd all gets power so somehow there is a connection or faulty ingition switch problem. PLEASE HELP with ideas on what to check...Im not a technician but I can ask the Nissan service folks to check for me. Thanks