i have a 99 dohc auto. my car has idle rough at stops a few times out of no where it seemed like the car was about to shut and the rpm's varied alot. when i opend the hood the motor was moving foward and backward with the rpm's alot. my problem was shitty gas i put injector cleaner and some stuff to get water out of the gas just in case and it worked fine afterwards.just a thought but the ignition check is a good thing maby you could sind sometion that no one elst thought of