Throttle Body Cleaning 2JZ 3.0L Inline 6 Lexus GS300 and IS300

Here's how to clean the throttle body and mass air flow sensor on a Toyota or Lexus 2JZ engine.

A throttle body is the butterfly valve that controls air intake into your engine. A dirty throttle body is often the cause of rough idle, poor throttle response and poor fuel economy. Carbon buildup often comes from the PCV (positive crankcase ventilation) hose that is routed from the valve cover to the intake to be re-burned.

Cleaning your throttle body and mass airflow sensor will yield noticeably better throttle response and a smoother idle.

The procedure involves removing the air box and intake tubes with a couple of 10mm bolts. Its also a good time to change the engine air filter. Once the engine cover is removed, the hose clamp securing the intake tube to the throttle body can be loosened and tube pulled off yielding access to the butterfly valve.

Since these cars are drive by wire, the ignition must be in the ON position (not started) in order to move the throttle cable and therefore the butterfly valve for cleaning. Spray throttle body cleaner and use a toothbrush and rag to clean the valve, being careful not to disturb the position of the valve while its open, as damage to the throttle motor can be inflicted.

The mass air flow sensor could be cleaned using sensor cleaner or electrical contact cleaner and should be allowed to dry before re-installation.

After putting everything back together the check engine light may illuminate due to the engine chocking on the throttle body cleaner. This can be cleared by pulling the battery terminal for 5 min to reset the ECU.

Take the vehicle for a nice long drive so it relearns your driving style with the newly cleaned throttle body.


Applies to Lexus GS300, SC300 and IS300, Toyota Altezza, Crown and Aristo.