Random idle RPM surges and engine stumbling
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2009 S550 AMG sport pckg. 2014 Ford F-150 Lariat Supercrewcab
Random idle RPM surges and engine stumbling
Hey everyone. So I thought I'd share a solution to an issue I had had for while. Might not apply for everyone but it was super cheap and simple fix. My engine never seemed to run smooth as it should. I would get some noticeable idle rpm surges and occasional momentary stumbling. Checked my fuel trims and it was running alittle on the rich side at +9% and it would get better at 2000rpm snap throttle. So vacuum leak was my suspicion. So I took off the air box and tried wiggling tubes to see if rpms changed. If I wiggled the MAF sensor/intake elbow assembly the rpms would go everywhere. So I suspected the rubber gaskets in the intake elbow. One sits on the throttle body and is subjected to alot more heat than the other which sits between the MAF sensor housing/ intake air elbow. When I removed that gasket it felt like it was made of plastic and the elbow came right off of the throttle body with little to no effort. I went to the dealer and bought two new gaskets and the new one was soft and pliable. And when I went to put the elbow back on, it took some effort and wiggling which was a good sign. I then reset the adaptation data. Now engine runs smooth and fuel trim is down to about +2!!! definite fix.
Here is a pic of the elbow Im talking which is on the left and the gaskets I replaced are the two red ones. One of them was hard and brittle and felt like plastic and probably wasnt sealing very well and allowing unmetered air to enter
Here is a pic of the elbow Im talking which is on the left and the gaskets I replaced are the two red ones. One of them was hard and brittle and felt like plastic and probably wasnt sealing very well and allowing unmetered air to enter