Discussion Starter · #1 ·
1991 - my speedometer has become slow on it's on with no changes made to the truck. It ranges from 12 to 15 mph slow depending on your speed. I have checked it with a Garmin GPS to verify. I replaced the instrument cluster with a working used unit 2 years ago and checked it at that time with GPS and it was spot on. Any ideas on what is going on?