03 suburban speedometer

speedometer wont go below 25 when stoped and runs 25 mph over what its actually going? Any ideas?

I had the same problem with the speedometer in my car. I found a website where I had it fixed for $140. They rebuild the entire cluster the guy said that all the gauges in the instument cluster are driven by the same type of motors and that I should replacce all of them before the were out. It made sence to me since the rpm's gauge was beginning to act weird. anyways here is the addres in case you wanna check it out.
http://www.speedometergaugerepair.com