I have a 1979 Chevy Camaro and when ever I turn the car on so it only lights up my dash, my RPM gauge goes all over the place, and the engine isn’t even turn on yet. And also before i even put the keys in the ignition, the RPM is sitting at 10. What should I do to fix this?
Have a proper diagnosis done/
If there’s a hint of rust on the vehicle, look for poor ground connections.
Find a shop that specializes in automotive electrical systems. This is a clear wiring problem and it’ll take a knowledge of and access to wiring schematics and multimeter use to find out where it is. You could possibly isolate it to a specific circuit by removing fuses one at a time until the problem goes away, but that can be tricky becaue all of your circuitry essentially is connected via a common ground…your chassis.