The Toyota Rav 4 has a completely computer-controlled carburation system that prevents the idle from being adjusted manually. There are, however, some things you can do to increase idle speed and improve the performance of your vehicle. The idle speed control (ISC) is responsible for the operation of the carburettor and meters the amount of fuel that is allowed through the system. The problem is often a sticky or gummed-up speed-control valve. Cleaning the ISC valve will greatly increase any loss in rpm's and get your Rav 4 running more efficiently.
Remove the air cleaner from the top of the Toyota Rav 4 engine with an open-end wrench and set it off to the side. Locate the idle speed-control valve that is positioned at the base of the throttle body.
Detach the throttle body from the engine with a socket wrench and then separate the idle speed-control valve from the throttle body. Place the control valve on a towel or old cloth and coat the valve and throttle body with throttle body cleaner by spraying the cleaner on the inside and outside of the valve.
Clean the valve and throttle body by wiping it dry with a towel to remove any debris or oil. Spray a second coat of valve cleaner on the control valve and throttle body and use an old toothbrush to remove any remaining oil or gummy material from them. Wipe dry with a towel.
Verify there is no cloth material or any debris remaining on the parts and place the control valve back inside the throttle body. Attach the throttle body assembly back on the engine and secure with a socket wrench.
Place the air cleaner back on top of the throttle body and secure with an open-end wrench. Start the engine and verify the idle is operating better. When you are satisfied, shut off the engine.
Always be careful and avoid, if possible, working around a hot engine.