Beretta.net

Engine tests show my engine to be idling around 800 rpm, I believe is what the dude said. Anyway, my tachometer shows it to be around 4000 rpm, and the problem keeps getting worse. I probably won't be too long before it pegs out on idle. It's an automatic, so the tach is mainly "gingerbread" but I would like to have 100% of my car working. Any ideas as to what this could be? Bad wiring maybe?

Generally speaking the electric tachs have internal calibration potentiometers or resistors.
I suspect something like that is going south. I don't believe it can be corrected without breaking into the gauge cluster.
My trip odometer is getting very difficult to reset and will probably need to be repaired.
I'm sure other people repair them, but I know the dealer will send them out for repair to maintain odometer integrity.