Any where from 211 mph pulling into my drive to a steady 29-33 mph down the highway. Any ideas ?? what to look at.

Probably the speed sensor. What kind of digital speedo is this? An aftermarket gauge or an OEM dash?

The sender for an electronic meter such as this generates low level signals used by the gauge, much like the electronic pickup in your distributor, and as such, is subject to noise disturbances, and other unwanted currents, such as 'ground loops' in the wiring/ chassis/ engine.

make sure you are using shielded wire, and try grounding the shield at ONE END ONLY of the run.

Run the wiring neatly along the body, clipped as close to the body as possible, because the ground of the unibody helps form a signal ground.

It may be picking up noise from the ignition or alternator, or simply have a ground loop from one end to the other.

If it is on an '80s to early '90s Mopar, then it is likely the speed/distance sensor has failed. It is a pretty common failure and not too bad to replace (though depending on how badly your '80s Dodge is leaking oil, it can be a messy job ).