speedometer starts at 10 mph

[dynamite196]

I searched but with no luck so here it goes. When the truck is turned off the speedometer drops to 0 mph like it's supposed to however when it's on it will hover around 10-15 mph when I'm not moving and the speedometer also reads much faster when I'm moving (i.e it shows 45 and i'm doing 30 or something like that). Does anyone know what could be causing this?

 

[SkanlaxJMO]

have you put on reverse glow gauges or anything similar to that?

 

[dynamite196]

nope