My nav was working great the first couple days I had it. Now all of the sudden the red arrow jumps up and down. Could this be because I don't have the vss wire hooked up? Even though I dont the arrow, for the first few days if I remember moved really smoothly along with the background. Now its all jittery.

Could this be because I don't have the vss wire hooked up?

Yes

Im thinking the same thing. Im bringing this back to the installer to have him hook that wire up.