The tachometer in my 90 Bonneville LE reads high, shift points seem to be correct. Could this just be a inaccuracy in the display? Are there resistors I can replace to remedy the situation. It isn't a huge deal, but its one of the only things wrong with my bonneville.

How high?

Have you attached an inductive-pickup meter to measure the difference?

I haven't. At idle it reads 2000ish, on acceleration it will go up fairly high, sometimes just sit at 7k until it shifts. The motor is definitely not working that hard, and idle was determined to be 880-900.

Wow yeah if it was spinning that fast, it wouldn't do it for long.

What does it read with the key on and engine stopped?

With key out it reads below the 0 and when key is turned to on position goes barely above 0

I wonder if it could be the stepper motor itself at fault.There must be places that re-condition them.

On one of those it'd be better to replace it if it is a stepper motor. If the movement is linear and consistent, it'* probably not the stepper motor.

It does seem to be linear let me see if I can get a video,

DId you change your harmonic balancer or crank sensor lately

If you can get your hands on a scanner, you can read live data and get information on the engine speed the PCM is reading.

GM is not really known for gauge accuracy, but this does seem to be pretty bad, even for GM norms. Stepper motor issues in this gen are pretty much unheard of. It may be worth the trouble to try and source a replacement cluster just in case.