Tachometer on the fritz?

[Boosted_GR33K]

Have a 97 bonneville SSEI with a motor out of a 98 GTP. I put the ZZPerformance power log on the other day, and while I was installing it accidentally cracked the coolant temp sensor comming out of the lower intake manifold. Grabbed a new sensor, and it seems to read fine but ever since installing the power log the Tachometer has been possessed. If Im just coasting/idling it reads normal, but as soon as I put on the throttle it just starts jumping everywhere. Bad cluster or maybe I bumped something else important on install? -Ben

[nos4blood70]

Tach usually acts up when there is a crank position sensor issue, but if the car isn't shutting down or struggling to run, then you might just have a wonky tach needle.

[Boosted_GR33K]

Tach usually acts up when there is a crank position sensor issue, but if the car isn't shutting down or struggling to run, then you might just have a wonky tach needle.

After its warm/hot, I noticed if I stop to say go to grocery store, pay bill, etc. and try to start it 10-15min later, when I start it its really huffin/chuggin for a few seconds but then evens right out and is fine. Is there a fix for a wonky tach needle?

[1oldman]

Tach usually acts up when there is a crank position sensor issue, but if the car isn't shutting down or struggling to run, then you might just have a wonky tach needle.

After its warm/hot, I noticed if I stop to say go to grocery store, pay bill, etc. and try to start it 10-15min later, when I start it its really huffin/chuggin for a few seconds but then evens right out and is fine. Is there a fix for a wonky tach needle?

When the Tach on my ole '92 went on the "fritz", it was the ICM under the 3 coil packs that was the root cause. - BC