If the battery was recently disconnected or run dead, the Engine Computer has to relearn "minimum throttle" before it will know when it must be in control of idle speed. To meet the conditions for the relearn to take place, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the brake or gas pedals.
When the relearn is done, you will also get the nice "idle flare-up" to 1500 rpm when you start the engine. If that doesn't occur, your mechanic can connect a scanner that can command an increase in engine speed in 200 rpm increments to see if the automatic idle speed motor is working.
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Friday, February 4th, 2011 AT 10:49 PM