1986 Nissan Truck ignition problems

Hey 2 pros, i own a 1986 nissan 720 4x4. the problem is that the intake side coil cuts out from time to time. i've replaced the coil and igniter several times and still no luck. the tach runs off the intake side so it also cuts out when it feels like it. i cut the tach out of the equasion thinking it might be shorting out, still no luck. when it hits three grand the exaust side is supposed to cut and run off of the intake side but instead it just pops like its hitting a rev limiter. i've done the freezing of the computer trick but still no signal to the intake side. im getting power to it but no signal. oh and i've also replaced the distributor. so im at a loss here, any information on the truck specifically would be very helpful. thank you very much 2 pros.