tach acting funny??
 

For some reason today i noticed that the tach is acting funny. There is also a sqeeking sound coming from under the hood. Maybe one of the pulleys or something. But my tach seems to be extra sensitive. Also when idleing the tach sits at 1100 rpms instead of 600. The truck is idleing normal.
any ideas??

Could be a grounding problem

thanks ackattack. Where would the ground be? Should i just pull the dash and check?

Is this a factory tach?

I have had bad insturment cluster grounds do lots of really weird things....i have ended up just running a wire from one of the screws on the back of my insturment cluster to a metal part on my dash board.......

yeah it is factory. I am assuming that it is a bad ground. I will have to tear it apart this coming weekend.
thanks yall