Not sure?

Not sure whats going on, with the key in the on position everything works fine but, when I start the car everything goes haywire. After the car is started for a short time mostly everything returns to normal except the tach stays pegged, at least thats all that is obvious. Is there anything in the starter or ignition that could be causing this sort of actions?

What year car and which engine?

92 Rs 3.1

yeah more details

I just bought this 92 Camaro and it has a few problems the fan never kicks on and the tach always stays pegged out. So I took the dash apart and detached the cluster. Then the tach went to normal even after I put it back on with the the key on its not til I start it that it pegs out it seems like for a split second it tries to act right but it never stays. Also sometimes the radio makes a wobing sound repetitively not all the time though useualy right after the car is started then it stops.

Check the wires at the distributor, make sure the white one is ok. I believe there is also a noise filter under the rotor in the distributor.