How to Clean or Replace a Faulty Throttle Body

Keeping your throttle body clean is a good way to maintain or improve fuel economy. A dirty throttle body reduces an engine's ability to breathe just as a dirty air cleaner would.

Tools and Materials

• A phillips or flat head screwdriver (depending on the type of clamp used on the throttle body intake hose).
• A can of throttle body cleaner.

Remove Hose from Throttle Body

With the engine off, locate the air filter case. Follow the large hose from the air filter case until you reach the clamp connecting this hose to the engine. This hose is clamped to the throttle body. Loosen this clamp and remove the hose from the throttle body.

Spray Cleaner into Throttle Body

Before you spray, pay attention to the location of the air mass flow sensor which is usually attached to the throttle body. Do not spray the air mass flow sensor. Using a can of throttle body cleaner, spray short quick bursts into the throttle body while moving the throttle butterfly from the closed to the full throttle position. Do not use one continuous burst.

This process gets dirt and other deposits off of the throttle butterfly, throttle body walls, and idle bypass valve. Dirt accumulation disrupts normal airflow causing a rough idle and decreased engine performance.

Reconnect the Hose

Reconnect the hose you detached in step one and tighten the clamp.

Test Drive

Start the engine and rev the engine a few times, then take it for a test drive. When you return, let the engine idle about two minutes and see if the idle is smooth. If it is not, there may be other problems at work and not just a dirty throttle body.

Throttle Body Replacement

If the problem is more than just a dirty throttle body, and the part is actually defective or broken, it may need to be replaced.

Tools

• Screwdrivers
• Set of ¼-inch sockets
• ¼-inch ratchet
• Needle nose pliers

Detach the Air Cleaner

First, detach the air cleaner. There will be some hoses here. These are the ducts that pass air to the engine. Remove them as well. Make sure you have removed the electrical supply to the air flow. Any other sensor that might be attached here (there might be a sensor to measure the temperature of air taken in) must also be removed.

Deactivate the Idle Air Control

You cannot loosen the throttle body without detaching the air control first. You can find this just before you reach the throttle body, on either side of it. Detach it.

Deactivate the Throttle Position Sensor

Disconnect the throttle position sensor from the throttle body.

Disconnect Throttle Cables

Open the throttle body all the way by hand. Disconnect the throttle cables one by one. You need to make sure to first open the throttle body so that the cables will have some slack that will allow you to remove them.

Remove Water Hoses (If Applicable)

Not all vehicles have water hoses connected to the throttle body, but some do. If your vehicle has water hoses that lead to the throttle body, remove the hose clamps and then pull the hoses off. Any suitable set of pliers should help you in this.

Remove Retaining Bolts for Throttle Body

On most vehicles, there will be four bolts that attach the throttle body to the intake manifold. Remove them. Lift the throttle body off the intake manifold. You'll find a gasket here. You have to be cautious with this, because it will be the same one you'll use after replacing the throttle body.

Install New Throttle Body

Ensuring that the metal gasket is in place, attach the new throttle body to the intake manifold and tighten the four bolts securely. Make sure to look in a car repair manual for your vehicle to get the proper torque specification for tightening the bolts.

Reconnect Components

Reconnect all of the disconnected components, one by one, in the backward order of how you removed them. Start with the water hoses and work your way backward until you have reinstalled and connected the air cleaner assembly.

Instructions for replacing a faulty throttle body can be different from one car to another. An automotive manual such as Haynes or something similar could give more precise instructions.