The last step in both procedures (idle speed and timing) is to remove the wire bridging the TEN and GND terminals in the diagnostic box. There is no reference in anything I've read, including the factory repair manual, to disconnecting the battery.
hmmm, it must be in the instructions on miatanet. I know I didn't make it up because I've read of some people even pumping the brake pedal with the battery disconnected to reset the ECU.
