ok my spedo in my truck is freaking out...... ya i know not my camaro....but anyhow its a 1992 chevy truck...and i have replaced my vss sensor...the drac moduel...and tried a differet cluster..... the spedo reads fine kinda its a tab bit slow to respond but once i hit 41 it stops and jump back and forth from 41-38...then if i drop it in drive it shoots down to 30 and wont go over it.....what elses can be wrong?

 

anyone?