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Rough idling in gear and park

my 2010 corolla idles at 600 rpm and shakes even after cleaning the maf sensor and throttle body, as well as replacing the motor mount, ive noticed that a can of seafoam in the gas helps bring the idle back up a bit but only temporarily, how can i get the idle rpm to normal so it doesn’t shake and not spend a small fortune on seafoam?

When did you last replace the spark plugs, the fuel filter, and the air filter???


right now its got 161k miles, spark plugs at about 120k, air filter at about 159k, fuel filter though not sure can be replaced without taking off the fuel tank

Coils? Spark plug wires? Ignition components go bad over time, not just spark plugs.

And is the check engine light on?

no check engine light

Check for diagnostic codes anyway; there may be some pending. My guess is either an ignition system problem or fuel pressure problem. If neither of those, check compression.

600 rpm at idle seems pretty low to me. Is that correct? Also, check your transmission fluid levels.

If you want a smoother idle you may have to replace all of the engine mounts and not with cheap parts.

Customers seem to complain about idle quality in the fall, idle speed and engine load is different with the A/C off. One must consider the value of a perfect idle, personally I’m not going to speed $5 to improve the idle quality of the engine in my car.