Tach Issue

[CJCJ]

Tach intemittently reads zero but reads fine when accelerating. Seems to happen only occasionally after a warm start. Any ideas? I pulled it and cleaned it checked resistance all looks fine.

 

[hoodshauler]

are the wires where the sending unit is exposed if so that can cause you problems.

 

[argve]

sounds like she's dragging a leg per say... time to replace it. But BJ is right check the wires first because bad wiring can cause problems and with the age on these trucks wiring is a concern. You can only get the tach sender from FORD.