1997 Chrysler Concorde Idles Weird

First of all, get it up to speed on the highway, then coast for at least seven seconds without touching the brake or gas pedal. This will trigger the engine computer to relearn minimum throttle. If that is lost from memory, the computer won't know when to control idle speed and when you have your foot on the pedal.

With a new fuel injector, fuel metering is different than before. It takes a while of driving for the computer to relearn "short term fuel trims" before it can adjust fuel mixture for proper operation. The same thing can happen when the battery is disconnected or run dead.

If these things don't work, take the car back when the mechanic can have it long enough to reproduce the same driving conditions as when the problem occurs.

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