my spedometer randomly will drop to 0 while driving then kick back into the speed I was at momentarily after…
1990 Auto 240SX is the car.
if its cable it might be binding thats what it did in my gts it didnt go to zero however but it went up in increments. i just changed it and it was all good.
There is no speedo cable in a 240.
There is your speed sensor (passenger side at the back of the tranny) and your cluster.
I would check my grounds at the cluster then have a look at the sensor. pull it out and check to see if any teeth are broken on it. If not i bet it’s a wiring issue