Hey... so what does it mean if my tachometer is sitting up at 5500rpm but the engine is clearly not revving that high. When I turn the car off, it settles around 3500rpm... i'm guessing a sensor of some sort, but figure if it was a sensor it should settle back down to zero when the car is off... any thoughts?

 

Most probably a bad stepper motor. See the link for part needed

https://www.ebay.com/itm/7-X-Stepper...VXnwBW&vxp=mtr

Hope its help