Speedometer messing up

[jwfrauts]

I am about 1600 miles from my house in my truck and the speedometer keeps messing up. I was doing 86 mph according to the gps and the speedometer was reading about 140 mph. If I shut the truck off for a little bit it will go down a little at a time. I can go 70 and it will read 100 and then after shutting it off it I can go 70 and it will read 80. It will finally go back to the correct mph after setting overnight. It has done this twice on my trip. Has anybody else had this problem or know how to fix it. I was trying to go by my rpms but got pulled over for doing 90 in an 80 when the tach quit working for a few miles. I just got a warning though, thank God.

 

[StrokerDude]

I didn't think our speedometers actually went up to 140mph

 

[Blue2Fifty]

Mine has done that a couple times, I did the odo button pushed in while you turn the key on thing, cycle to the test gauge function and it will reset it.

 

[jwfrauts]

Thanks I will try that. The speedometer only goes to a 100 but is was pointing straight down.