I had a coil go bad on the number 2 cylinder (passenger side front). I had an extra one, but it was for the rear. The front and rear coils have two different part numbers. I went ahead and installed the extra coil and my idle is really low. Like around 625 rpm. I did the ecu reset procedure, idle air volume learning, accelerator pedal release position learning, throttle valve closed position. There is still no difference in idle. Any ideas or answer to my original question?