idling troubles

[retroman]

I have a 2000 Tacoma with the V-6 and a manual transmission. Trouble is.....the idle speed is not consistant. On cold starts it acts fine(1500rpm and settles down to 750)..but once the engine reaches operating temp the idle returns to 1100, or 1500 or somewhere in between. Sometimes while at a stop with the idle at 750, I can watch the idle climb on its own back to 1500.
I have replaced the Idle Air Control Valve, checked the MAF, looked for vacuum leaks but....nuthin". Where to next? Whaddya think about having a defective coolant temp sensor? Thanks guys!

[Cobb]

I had the idle vary and a check engine light when the connector to the thingie onthe passenger side rear of the intake come undone. If I set the cruse to 35mph, it would go from 600-1500 and back rpms.