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

I am ASE mechanic as side job.

by in Kingfisher, OK on January 16, 2012
1 answer 1 comment
ANSWER by , January 16, 2012
make sure you have the correct tire size on the car. otherwise, the trans gear inside the governor may be at fault. Roy
COMMENT by , January 17, 2012
The tires have not been replaced, it just started doing this about 1 week ago. I suspect the speed sensor is failing.