Perform intake cleaning first. Sounds like its hunting for idle speed.
Operate engine until cooling fan comes on. Turn engine off. Connect tachometer. Disconnect 2-wire connector from Idle Air Control Valve (IACV). See Fig 3.
Restart engine and hold at 1000 RPM momentarily. Let engine return to idle. Check base idle speed with M/T in Neutral (A/T in "N" or "P") and all accessories, including cooling fan, off. Base idle speed should be 430-530 RPM. If necessary, turn screw to adjust base idle speed. See Fig 4.
Turn ignition off. Reconnect 2-wire IACV connector. Remove BACK-UP fuse (7.5-amp) in main underhood fuse box for 10 seconds to reset PCM. Start engine and allow to idle for one minute. Check idle speed. Idle speed should be as specified.
Also helpful are some vacuum diagrams.
Images (Click to enlarge)
Thursday, January 30th, 2014 AT 7:04 PM