2011 honda Accord 4 cyl idles like it wants to turn off. Other mechanics said there were no vacuum leaks but they think it's because of carbon buildup due to previous bad coils. It has been several weeks since that assessment. In between that time, the idling issue seemed to be gone and then returns. I've used cleaning additives such as Gumout yet it persists. Acceleration and cruising is fine. The problem started about two weeks after installing aftermarket coils, since then they were removed and replaced with the stock coils. The car's Iridium sparkplugs are several months old.
My car has a manual transmission.
If you are having rough idles only and engine runs good above idle then have engine mounts checked since they will cause engine vibration and think it is running rough. If okay then have a mechanic check computer sensors and intake systems for problems. You may have a sensor that is not reading correct at idle or have a hard to detect vacuum leak. If you have the VTEC engine your cam control may not be working correct and will cause rough idle. Make sure you only use correct oils.
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