Hesitation Rough Speedometer Stops

[SamplesZ]

Have an 88 300 ZX non turbo Coupe. Automatic. Couple of months ago there was a SEVER hesitation., lurching, loss of power. The speedometer stopped working went to zero. Pulled over had towed. Once at shop problem stopped. Happened again couple of weeks later. Mechanic saw and said was a cable to the transmission (speed sensor cable). Ordered replaced worked for a while and then started same problem. Progressed once to the point the speedometer going from zero all the way to 140 and would then "flicker" all while at a stop light. During this same period I have had the transmission tend to slip and rev up and slowly engage the gear (similar to a failing clutch) and confident the 2 problems not related. Anyhow some have said throttle sensor? Computer? A relay that is giving off too many volts? Im sure there will be a bunch of questions so go...