Problems keeping our 2000 Toyota Avalon running after startup

Occasionally we trouble keeping our 2000 Toyota Avalon running at idle speed after starting up. The car, 250000 miles, does well at everything else but at these times it stalls out immediately after starting. The only thing we’ve found to do to overcome the problem, is to race the engine faster than idle while stepping on the brake to create enough drag to control the car when we come to a stop, otherwise the engine will stall out. After a short time of driving the engine idle has corrected itself. Out mechanic thinks it’s a problem with an electronic module that governs the idle/speed, but needs to test the car when it has the problem. And like most problems, it doesn’t happen when the car is at the shop. Anyone with an Avalon have or had this problem? John

Does this problem seem related to using the brakes? If so I would start by checking out vacuum lines.

Use MAF (Mass Air Flow) Sensor Cleaner, and Throttle Body Cleaner in the intake track, and clean the idle air control valve passages. This is a simple procedure.

The problem might be with the Idle Air Control circuit.

On the throttle body is a component called the Idle Air Control/Air By Pass motor. This is what controls the engine idle anytime the accelerator is released. When this component gets old it can become lazy where it doesn’t go the proper position for the idle condition and the engine stalls. One of the ways to confirm this is the problem is the engine can be prevented from stalling by slightly stepping on accelerator while applying the brake. Another way to check for a defective IAC/ABP motor is, while the engine is idling, take a screwdriver and with the handle tap on the IAC/ABP motor. If the idle speed changes when doing this it usually indicates a defective IAC/ABP motor.