95 f150 the speedometer works but doesnt stay on the right speed. What does this mean
 

My 95 f150s speedometer works but jumps all over the place driving down the road. It's an electric speedo what do I do.

I would start by checking fuse 18. If that’s good check the speed sensor, IIRC it’s on the rear diff, unplug and look for corrosion.

Fuses
 

# 18 fuse is good and no corrosion on the speed sensor.

I just found this, hope it helps Speedo fix

Read the TSB in this caption:

https://www.supermotors.net/getfile/...ster-front.jpg
(phone app link)