when i reach about 60 mph the needle jumps around on my 95 f150. any ideas on why this happens and how i could fix it?

 

If there are metal shavings built up on the ABS sensor in the rear axle, clean them off. Chock at least 1 front tire front & back, lift at least 1 rear tire off the ground, shift to N & release the e-brake. Then observe the tone ring thru the ABS sensor hole as you turn the d'shaft by hand; if it's damaged in any way, replace it. If not, replace the PSOM. They're known to go bad like that.

For photos & diagrams of the rear axle, click my signature link & look in the 8.8" Axle album.