On my 86 suzuki samuari when you crank it little thing up tha tack goes straight to 8,200 rpms but motor is idlin what could it be i have know idea how it works!
hook up an aftermarket tach, prolly be easier than trouble shooting
x2 on new tach. but usually a grounding problem. check on yer fire wall on all the grounds with screws. they have a tendency to get rusty
Ill check that first i kinda wanna keep it stock on tha dash for now thats why i want to fix tha stock one.