'97 Ultra no tach revisted

[kmax1]

I cleaned the coil pack connector. Every once in awhile the tach will die when driving. It is always ok after a restart.

One time the car died while at a stoplight. Restarted fine.

Is this sign of a crank sensor failure? MIL never lights up.

Does crank sensor replacement require the alignment tool? Reading the procedure in the factory manual makes no mention of using the tool.

Thanks again.

[BNaylor]

Your symptom sounds consistent with a flaky crank position sensor (CKPS) and it is possible no DTC error codes will set triggering a SES/CEL Mil light. The 18X pulses from the CKPS are also used for the tach processed by the ICM. Also, it would be a good idea to get the Ignition Control Module (ICM) tested.

The special tool needed will be a harmonic balancer puller with specially threaded and sized bolts to fit your harmonic balancer. The 18X CKPS is located behind the harmonic balancer.