Desperately seeking answer (now you know I'm a child of 80's!!)

1. Needed to replace alternator and battery. Replaced them at same time and went through idle re-learn process.
2. After first re-learn, idle rpm went up to 680 - 700. Turned ignition off and restarted 3 times and car and idled smoothly. Did NOT drive around for few miles since they started fine and smooth
3. Next day, car started fine and smooth, went grocery shopping (2 miles from my house). Shopped about 50 min, came back to start my car, BAD idling 450-350 RPM and shuts off.
4. Drove as is engine shutting off on every red light (About 5 of them). I was able to restart the car every time on Green light and got my self home.
5. Disconnect the negative of the battery, waited about 5 MIN and reconnect. Did the Second Idle re-learn and successful. Idle RPM stable at 680-700.
6. After second re-learn, took the car and drove highway about 30 miles and returned home. Started my car from driveway about 4 times after 30 miles of highway, Camry started fine and smooth idling
7. This morning which is about 48 hours since #6, bad idling. 450-300 RPM and shuts off.
8. Multimeter shows battery at 12.6V with engine off and hovers around 13.6V when idling
9. Just did third re-learn and idles at smooth 680-700

Any suggestions on what to look for? Could the problem be somewhere else?

 

Try cleaning the throttle body and throttle plate. The internet has video's on this. The engine type is a 2AZFE.

It appears "crud" can build up on the throttle bore and edges of the throttle plate. This can cause the engine computer to have problems determining the actually throttle position at idle.