My Lexus ES300 Has an Idle Problem

by Andrea Stein

Introduced in 1989, the Lexus ES300 is a luxury sedan and part of the family of ES300 luxury cars manufactured by Lexus. The Lexus ES300 can develop idle problems due to a dirty idle air control -- IAC -- valve.


The idle air control valve is an electronically-operated valve with a tapered section at one end. This section expands out and retracts in to either block or permit air to flow past the Lexus ES300 throttle and enter the internal combustion engine.


The electronic control module in the Lexus ES300 sends out a signal to the idle air control motor to adjust the engine’s idling speed. The idle air control motor then moves the valve appropriately to decrease or increase air flow.

Dirty IAC Valve

Dirt or debris can clog the idle air control valve, impairing its function and causing it to stick in the shut position. This decreases air flow to the engine, resulting in a low idle speed or stalling. Remove the idle air control valve and spray carburetor cleaner on the valve needle to clear away any sediment buildup. If this fails to resolve the problem, replace the IAC valve.

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