Originally Posted by Nuke
The 05's and early '06's have a chronic issue with the stepper motors in the gauges. Google "stepper motors Ford Mustang" and you'll likely get a lot of supporting info. I understand that someone on ebay will replace the stepper motors if you send them the cluster. It didn't seem overly expensive, IIRC.
+1 when i purchased my car, the tach, fuel, and speedometer stepper motors were all crapping out. about $30 on Ebay and a $5 walmart soldering iron, and all's better.