1990 Camaro RS

For some reason the in dash tach goes all the way over to 7 grand even if I'm just cruising along at 20 MPH or driving down the road at 70. Sometimes it comes back over to a range in the lowe lines but any throttle input & away it goes.
 
What's up with that :)
 
CCarRocks

No sugestions other than make sure your wire connectors are tight on the tranny,

your instrumant cluster is going out. mine does it with the speedo but mine stop's at 27 mph. it's expensive to get fixed. i would just get an after market tach.

The ole instrument cluster going out thing. Man what a bummer :) I guess now it's time to get an after market gage setup :)
Thanks for the input, I had no idea where or what could be going on. Hopefully the speedo is correct or I'll ge a ticket :)
CCarRocks

So the tach gets its signal from the transmission. The trans was rebuilt about 2 months ago according to the man I bought the car from. I'll get underneath & check them.
 
I thought the tach got its signal from the distributor.

Is it a V6 or a 305?

It is a V6 car.
 
Which transmission should this have some with a 700R4 or ?

You should have a 700R4 (a pretty lightweight version at least).  Your tach signal should come from a cam or crank signal through the ign control module, possible through your computer, and then to your gauges. I'll check a schematic in the morning, unless somebody else has one.

Had the exact same problem...

my car idles wierd.  It sits around 500, then jumps a little bit, and dies down to almost 100.  How do I go about fixing it so it is always at a constant idle?

I don't know about the factory tach, but my after-market tach is ran straight to my distributer.
Gixxer: If your car is TBI there should be an adjustable screw or knob on the side of the carb.
Adjust it slightly each way till you get it.