Have an issue with 1988 Turbo Rx7
Any time an electrical load is applied, especially headlights, while running the car the Rpm's will drop about 400 rpm. If I add any other electrical load, especially heater fan, then the tachometer will quit. When the tach quits there is no trailing spark, however power is still being supplied to the coils. If I turn the car off and back on the tach and trailing spark works again until I turn on the headlights and/or heater fan motor. Alternator checks good 14.8 Volts, Battery is good. All grounds appear to be good. Tried a different Trailing Coil Pack, Crank Angle Sensor, Headlight Switch with no change to the problem
The car still runs when tachometer dies.
Any help would be great.