Hello all,
The Sonata idles at 1800rpm in park/neutral. The idle doesn't change from cold start to full operating temp. When in gear the idle is pulled down to 900rpm and when the A/C compressor cycles the rpm will increase about 50rpm, so I think the idle control servo is working but I'm not sure. There is NO check engine light. The engine occasionally runs rough and lacks power. I removed and inspected the intake hose looking for leaks and found none.
I need your help!
Thanks

 

It's probably the ICS valve if there's no intake leaks. You can test it by removing the thing and plugging up the holes. Did you do a code scan anyway? Don't drive like that too much, as it will burn up your transmission.

 

Yes, tested for codes and found none. Today I drove it a little then parked for awhile, when I re-started it idled at 800RPM but as I drove it home the idle returned to 1800RPM.
I guess if I remove the IACS and plug the hole it would narrow it down a little, Throttle Position Sensor, IACS, or something else telling the IACS to open the throttle.

 

It won't idle high unless it gets air. It's either getting air from the IAC or an intake leak.