I know almost everyone's had it, or heard it. The infamous rev, up rev, down, repeat idle. It goes up about a grand, then drops back to where it's supposed to be, then revs right back up, then it keeps doing it over and over. Is there one thing that 'causes this? Obviosly my car is doing it.
What's weird is if I turn my vent on, it drops the idle a bit and stops.
