Corolla / Matrix 2009-13 :: Low Idle Between 600 And 800 RPMs And Vibration In Drive Or Reverse

I think I resolved the idle issue on my 2009 Corolla S with 82,500 miles and Automatic Transmission.

Symptoms:
Idled at between 600 and 800 rpms
Annoying vibration in drive and reverse, no vibration in park or neutral
On hard stops, the engine felt like it was going to die
Turning on the a/c would cause the idle to increase to 1000 rpms and the vibration would go away.

At 82,500 miles, I cleaned the throttle body which was extremely dirty.

Process:
Disconnect the positive battery cable
Remove the top of the air box and flex duct going to the throttle body
Disconnect the two coolant lines going to the throttle body, make sure and have a few old bolts to plug the lines so you do not lose too much coolant
Remove the electrical connector to the throttle body
Remove the vacumn line to the valve cover
Remove 2 bolts and 2 nuts (10mm) securing the throttle body to the intake.
The throttle body does not have a gasket, it is an o-ring which should be fine.
Once you have the throttle body off of the engine, clean it thoroughly with Chemtool throttle body cleaner.
The inside of the throttle body and throttle plate should look like shiny milled aluminum. when done.
Spray chemtool into the two ports where the antifreeze lines were connected. If possible use compressed air to blow out these ports.
Clean the inside of the intake and the mesh screen where the throttle body bolts to the intake.
Reassemble, connect the battery, crank the engine and just let it idle for a good 10 minutes

The 2009 Corolla S DOES NOT have a serviceable IAC. It is riveted on to the throttle body. This is why it is important to spray the cleaner in the antifreeze ports in order to clean it. These ports are the antifreeze bypass ports.