Had a scanner and it told me to replace idle air control valve which they did, I still get the check engine light. Re-scanned and light went off waiting for results. Car is not surging and happens only when parked, not driving. disconect battery and is ok, any ideas?

 

Tell us what the new CEL is for and there is your idea for the fix.

 

Excessive air into the intake (a leak) for whatever reason causes engine to idle too fast, that is reported as an "IACV" code even though the (expensive) valve may actually be OK. Look for hoses disconnected, broken FITV on the thermostat (if equipped), or throttle plate not closing all the way when gas pedal released. If all that is OK try closing down the air screw on the throttle body (NOT the throttle plate stop screw).