ok, so i have a stock 1990 camaro rs and my RPM going 70 are 4000... yes i typed that right... about a year ago it was at 3500-3750. why is the rpm so high? is the tach the problem or would it be a tranny or axle problem? oh, and brand new zoom clutch, so its not the clutch.

 

Your tach is reading high.

 

what should it be reading? and would that be the reason why it says my idle is 1250?

 

My tach is way off as well. I have the opposite problem though. When I plugged in an ALDL cable with WnALDL on my laptop it showed way different readings. For instance, when my tach says 4500 / redline WinALDL showed about 2400 RPM. I have to push it way past redline past 7000 to even try to touch 4500.

 

This is a common problem with our tachs. There is a resistor that goes bad on the driver board. Easy fix for it.

The electronics board here has a good thread on fixing them.

RBob.