question about tachometer problem

[rhawley1430]

I have a 1994 Taurus SHO 3.2 automatic and lately the tachometer hasn't been working right. After the engine gets to normal temperature, the tachometer fluctuates a lot and finally stops altogether. I have already read about various things that could cause this to happen. A friend of mine (a former mechanic for a local Ford dealership) has replaced the following parts: engine coil, crankshaft sensor, camshaft sensor, and ignition module. All these new parts helped the way the car runs but the tachometer is still fluctuating and stopping. Does anyone know any other reason the tach would be messing up? Thanks in advance.

 

[rubydist]

I once replaced a cam sensor and had it fail right away, so just because the cam sensor is new does not mean its good, and a bad cam sensor can cause those symptoms.

If not that, then you have a temperature-related issue with the wiring to the cam sensor, to the instrument panel, or with the tach itself or the pcm itself.

What codes do you have now?

 

[sperold]

If there are no start-up issues, it is the tach itself. I had one that would work when it felt like it, but in my case it was when you were driving along it would start to register.
Change the cluster.