mack1

Hi mcdonaldf and welcome to TSF,

The term speed sensor usually means the sensor at the transmission output that tells the vehicle speed. Engine rpm is taken from another sensor and that one might be problematic. I think the same sensor that looks at the cam gear for the spark is used for the engine rpm also. I think Ford calls that sensor VRS (Variable Reluctance Sensor).

The only print I have that shows that is for a 1990 4.0 L engine. A Tach signal goes from that module to the instrument cluster.

If you have electrical prints for your car, you can post them here and we will help you track down the problem.

Very Best Regards,
Mack1