If you have yet to fix your problem, a good place to go is the IACV or idle air control valve. It's located on the bottom of the throttle body with the two small coolant hoses, and wiring plug going into it. Take it off then remove the switch and check for free movement of the valve, good chance it'...

After installing a 1ZZFE engine in my 2003 Vibe it ran great except the idle, when cold it started and ran great then began to bog down and most of the time stalled, then when warmed up it was around 2100 rpm. I drove it like this for a month before I realized it was not going to come out of it. So ...