Speedometer is reading 20 to 30 mph too fast. on 2001 Buick Park Avenue

I am ASE mechanic as side job.

Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
1 answer 1 comment
make sure you have the correct tire size on the car.

otherwise, the trans gear inside the governor may be at fault.

Roy
The tires have not been replaced, it just started doing this about 1 week ago. I suspect the speed sensor is failing.