I recently purchased a 93 Mustang GT. The tachometer is at 0 when I turn the key on. After I start the engine, it is normal, at about 900 rpms, and after
5 seconds it moves up to 3500 rpms. It stays there unless I rev the engine past 3.5k or if i use my power windows, hazzards, A/C, etc. It jumps around erratically when turning pretty much anything electronic off or on.
Anyone know what might be going on here? I'd be greatfull for any help you could give.
Thanks, Moostang