The engine in my car has a high idle (around 950). This is a recurrent malfunction that I have corrected several times. I recently replaced the ECU's coolant sensor and connector. A bad contact was causing improper temp values to be read by the ECU. The ECU has a table of idle speed vs temp and will only control the idle air control valve correctly within a narrow temp range. This brought down the idle to 750. Idle rpm is back up to 950-1000. I am clear out of options. Timing and MAF voltage are correct. The resistance values of the IACV are within spec. Car has a smooth running engine with no misfires or hesitations. Don't suspect an air leak; but who knows. Any ideas from the experts?
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