i have a 97 kw t600 and the rpm gauge is struck on 1000 rpm while off or on and sometime it move up to 1500 rpm slowly while the truck is at idle or driving what can it b or where to start looking at to fix it thanks for yall help
I would unscrew the sensor from the housing and clean it off good as a cheap place to start. They get alot of oil and grease on them over time.