1999 solara v6 high idle

[bronzemaxell]

when i start the engine cold, i saw the rpm at around 1100 for 0.5 second, then went up to 1800, after a minutes or two, the engine has warmed up (needle is in middle between C and H) but the rpm still idle at 1800, what would cause problem? vacuum hose or idle air control?
it doesn't appear to be a um-metered vacuum leak as the car doesn't shake, and if i step on the gas pedal, the rpm can go up to 3 or 4k rpm like normally would, but as soon as i let go my foot, it drop back down to exactly 1800rpm

also
there are two small vacuum hoses from engine to the ACIS vacuum tank under the battery tray
does any know how are the two hoses connected on the vacuum tank?
i noticed at the end of one hose has a little white band marking on it and the other one doesn't

[fenixus]

it sounds like a vacuum leak. 1,800 rpm is a lot for idle. can you hear hissing under hood?

make sure you plugged all vacuum hoses correctly and they are good (can both hold vacuum and air can pass through).

other than that stuck IAC valve could be the culprit.

[pmesfun]

Sounds like the IACV went crazy.