The tachometer on my 1990 Bonneville has developed an acute fluttering problem. It'* jumping around by as much as 500rpm at idle and when I first begin to apply pressure to the gas pedal.

I don't notice any difference in the engine sound, at least, not that I can tell. Is this something I should worry about? Any good way to tell if it'* just the gauge that'* acting up, or is the steady engine sound all I need to hear to know that?

If the engine is not running like the tach is behaving, then I'd suspect the instrument cluster and or a bad connection between the cluster and PCM.

I have often wondered why they make it standard for cars with automatics to have tachs, but not cars with sticks.

Thanks for confirming that, I'll see if I can't find those connections and check them. It'* the only gauge that'* acting up, aside from the gas gauge that'* told me there'* more gas than there really is for years, now.

My rpm hit the needle at like 12,000 for a while pined all the way forward. It did reset itself and still works fine now.
Your 1990, I wonder if the gauge itself may be toast. (stepper motor) I am no exert in them but I do know there is a company that can rebuild them and have em back to ya in short order if it is not an electrical problem.
http://www.ebay.com/itm/Buick-Speedo...item415f2164b7