My Corolla 2014 has this issue where revs fluctuate quite a bit at idle, sometimes dropping to 4-500 revolutions and going back up. I changed the MAF sensor, cleaned the throttle body, replaced the air filter, replaced spark plugs, and it still does it. Also, there’s no CEL or codes. I took it to my mechanic and they couldn’t find anything wrong with it.

What could it be?

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  • ronin9981@alien.topB
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    1 year ago

    Check your oil fill cap gasket. Just replaced mine after having weird RPM drops when lifting off the gas and now it’s 99% gone. I had replaced MAF and did the idle relearn procedure but oddly this is what helped. You probably have a vacuum issue.

    2010 Rolla 1.8, 150k mi

    Car Car Nut on YouTube is invaluable