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What Is a Throttle Body?

Oct 12, 2021 ·

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Various systems exist under the hood of a vehicle to perform functions necessary to daily engine operation. The air intake system is among them.

The purpose of the air intake system is to allow air to reach the engine, an important step in the combustion process. Many different parts that make up this system, including the throttle body.

Continue reading to find out more about how the throttle body works and the specific role it plays within the air intake system.

What Does a Throttle Body Do?

Within the air intake system, there’s a housing unit that contains a throttle plate, which is a one of the components of the throttle body. Also known as a butterfly valve, this plate rotates on a shaft.

When a driver steps on the gas pedal, the throttle plate opens to allow air into the engine. When the pedal is released, the valve closes. This works to choke — or throttle — the airflow in the combustion chamber, which helps control the speed of the engine.

The throttle body can be found in different areas depending on a vehicle’s engine type. Older models usually feature a throttle body that is built directly into the carburetor, which is used for fuel injection.

Late-model fuel-injected engines have a throttle body usually located between the intake manifold and the air filter. The throttle body is connected mechanically to the gas pedal with a wire or cable.

Most engines feature electronic fuel injection. In this case, a throttle position sensor sends a signal to the electronic control unit (ECU) when the driver steps on the gas pedal. This prompts the airflow sensor to communicate with the computer as well, increasing the amount of fuel the injectors provide.

What Does a Throttle Body Spacer Do?

A part that some car owners like to add to their throttle body system is a throttle body spacer, which is a small metal circle typically installed between the air intake and throttle body itself. This part is used to change the amount of airflow going into the intake manifold.

Image credit: Summit Racing Equipment

A throttle body spacer works to maximize the amount of airflow to the engine by allowing in more air than usual. The goal is to increase the horsepower and fuel economy of an engine.

This increase in airflow and velocity can help improve performance because the engine doesn’t have to work as hard.

Signs That a Throttle Body Is Wearing Out

Like any other part, components of the throttle body system can start to wear out and experience issues. It’s important to pay attention to possible warning signs and get problems taken care of as soon as possible.

Signs of a failing throttle body part could include:

  • Dirt and other buildup: The housing of the throttle body can start to accumulate dirt and other deposits, which can cause the air/fuel flow to become interrupted.
  • Poor idling: A common sign that a throttle body isn’t operating effectively is poor or lower-than-normal idling. Stalling when pressing the gas pedal rapidly or after coming to a stop can occur.
  • Uneven acceleration: Air and fuel gets released into the engine when you press on the gas pedal, but a worn throttle body could prevent the engine from getting the power it needs. If your car is taking longer to gather speed, it could be a throttle body issue.
  • Leaks: The air/fuel flow can get disrupted from vacuum leaks, which can be caused by a throttle stop that’s wearing down or isn’t adjusted properly.
  • Electrical problems: Connection problems with the throttle body sensor can cause communication issues with the ECU, which result in a drop in power.

Be sure to take your vehicle to a trained technician to determine the source of the problem and get things running properly again!

Get Hands-On Experience With Air Intake Systems at UTI

Want to learn skills that can help you perform maintenance on vehicles? The Automotive Technology program at Universal Technical Institute (UTI) features courses and hands-on training that cover the fundamentals of automotive maintenance and repair.

Not only could this help you make repairs, you could apply this knowledge to a career in an in-demand industry.1 In fact, there are more than 73,000 estimated average annual automotive job openings available in the United States.41

Find out how you can get started by requesting more information today!

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1) UTI is an educational institution and cannot guarantee employment or salary.

2) For program outcome information and other disclosures, visit

41) For Automotive Service Technicians and Mechanics, the U.S. Bureau of Labor Statistics projects an annual average of 73,300 job openings between 2021 and 2031. Job openings include openings due to net employment changes and net replacements. See Table 1.10 Occupational separations and openings, projected 2021-31, U.S. Bureau of Labor Statistics,, viewed October 13, 2022. UTI is an educational institution and cannot guarantee employment or salary.

Universal Technical Institute of Illinois, Inc. is approved by the Division of Private Business and Vocational Schools of the Illinois Board of Higher Education.


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