L69 and LG4 ECM Compatability?
 

I've had an ignition problem on my 83 L69 5 speed for a while now. Every once in a while, it will randomly cut out like the key is being turned off and on rapidly. The cutting out continuously changes in frequency like morse code. The only visual indication I see is the tach drops suddenly towards zero RPM in sync with the ignition cutouts.

I've changed out the module and the pickup coil, (reluctor?). I connected a test light to the distributor power connection and ran it into the interior to see if it was a power problem. I've even disconnected the tach lead to eliminate the possibility that it was grounding out somehow. I didn't change out the coil as I have yet to solve any ignition problem in the past by doing this. I'm afraid that the computer might be at fault. I don't know what else to do.

Anyway, I might be able to get an ECM from an 84 LG4 5 speed from a T/A. Besides the difference in the chip, would this work as a troubleshooting aid or even a permanent fix if this solves the problem?

If it's not my chip causing the problem, can it be swapped to the new ECM so I can keep the same L69 fuel and timing profiles?

Thanks for any help someone could provide!

Larry