So, this afternoon after I left work I went to the paintball field to check in with my team, and when I left there.. when I got into town, my speedo went bizzerk.

It jumps from 50, 100, 10, 30, etc.. If I accel really slowly, it will be okay until I get to around 30mph, then it jumps all over the place.. Is it the sensor? Is the gauge bad? Any idea?

 

If its a cable driven speedo - the cable is messed up...

 

sounds like the vehicle speed sensor, if that applies to your truck.