Dodge: 1997 Sebring 2.0l ide - up and down

1997 Sebring 2.0l, a/t, - idles up and down.
Problem is worse when car is cold.
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I have change the oil - someone but 10w30 in it, and
i put in 5w30. I put can of seafoam in engine and fuel;
and it seems ot be better.
Intake and filter is clean.
No check engine light on.
Ideas?