I have a 2003 mercury mountaineer the Idel was going up and down when I was sitting in park the part store put it on there tester last night and said it showed my oxygen sensors have failed.. now when I put my truck in park the rpm will go from between 0-1 to between 1-2 and go back down and back up then it shuts off could it just be my oxygen sensors
The Oxygen Sensor is picking up an issue with the engine’s rpm change through the fuel air mixture. If an Oxygen Sensor was to fail, the computer will make the Idle Air Control Valve constantly move to try and correct the volume of air in the exhaust system. I suggest replacing the Oxygen Sensor and reset the computer.
If the engine continues to have an erratic idle, then I suggest cleaning or replacing the Idle Air Control Valve. If you need further assistance with the engine’s idle fluctuating, then seek out a professional, such as one from Your Mechanic, to help you.
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