I have an issue with my speedometer, when accelerating and decelerating, the speedometer is occasionally jumping fairly erratically. Any ideas on what this issue might be caused by?

 

speed sensor could be going out, but that would turn on the check engine light. is it on?? also the speedometer head could also be having an issue

 

the check engine light is on but im pretty sure that its due to an egr flow restriction... which is yet another issue that im having. With that, i've changed the egr valve and cleaned out the ports from that and the check engine light is still coming on.

 

need to check that code, could answer your question of whats wrong