Symptoms of a Bad or Failing Throttle Body

Schedule Vehicle Engine Mechanical Inspection
Service Area

$0.00

Upfront, Transparent Price
Average rating from 133,914 customers who received a Vehicle Engine Mechanical Inspection.

In today’s modern fuel injected cars, the throttle body is a critical piece of the air intake system that controls the amount of air flowing into the engine. The amount of air allowed in depends on how far the driver presses the accelerator pedal to the floor. As you press down on the pedal, the throttle position sensor receives a signal relative to where your foot is, ranging from all the way up (zero acceleration) to all the way down (full acceleration). This sensor relays the information to the car’s main computer — giving it constant updates as to the position of the throttle. The computer knows what to tell the fuel injection system in terms of how much more or less fuel to inject into the system based on the position of the pedal.

When this process is regulated properly, a perfect balance of air and fuel is introduced to your car’s engine, allowing it to run smoothly and perform at an optimum level. Here are 5 signs of a failing throttle body:

1.Grime Buildup

Dirt and grime can build up inside the housing, this being known as coking, and causing an interruption in air-fuel flow. As a result of not having an ordinarily smooth surface for the fuel and air to flow through, this delicate mixture is interrupted by a rough surface that causes an imbalance in the flow. Similar to dirt and grime, carbon deposits can create an uneven surface inside the walls of the throttle body, which can disrupt the atomization of the air-fuel mixture.

2. Electrical Problems

Electrical connection problems can cause inaccurate or intermittent information to be relayed to the car’s computer. As with any electrical connection, connectivity issues can cause a wide variety of unpredictable signals to be transmitted. In the case of the throttle body (and related sensor), when this happens it causes false information to be relayed to the car’s computer, resulting in faulty corrections to the air-fuel mixture. You may notice a switch into “limp-home” mode, where power to the car’s engine power is reduced and throttle operation is limited.

3. Airflow Disruptions from Vacuum Leaks or Throttle Stop

Vacuum leaks can disrupt the air-fuel flow because of an imbalanced airflow, which can cause throttle body pressure problems. The issue could also be an incorrectly adjusted throttle stop. This is a component that acts as a gate-keeper and establishes a minimum or maximum position for a throttle body plate to be opened or closed. A maladjusted stop wouldn’t allow in the correct amounts of air and fuel.

4. Poor or High Idle

When a throttle body is not functioning correctly, some noticeable characteristics may be poor or very low idle. This can include stalling when coming to a stop or very low idle after starting, or even stalling if the throttle is quickly pressed — resulting in the throttle body plate opening and closing very quickly.

In the case of a large vacuum leak, you may experience a very high idle because too much air is being allowed into the intake system. All of these symptoms will contribute to poor engine performance and, as a result, will cause your check engine light to come on.

5. Check engine light

The check engine light can indicate many issues within a car including a faulty throttle body. In more modern cars, an electronic throttle control (ETC) constantly monitors throttle body performance. Any problem detected with it will turn on the check engine light.

As a part of your regular service intervals, include the air induction service and fuel injection flush to clean out any carbon deposits and dirt. You will need to have the check engine light shut off by a qualified mechanic. This will include scanning your car’s computer system for fault codes to indicate problems with your fuel injection system and specifically throttle body components. These will give the mechanic an indicator as to what to check for and how to repair the problems.


Next Step

Schedule Vehicle Engine Mechanical Inspection

The most popular service booked by readers of this article is Vehicle Engine Mechanical Inspection. Yourmechanic’s technicians bring the dealership to you by performing this job at your home or office 7 days a week between 7AM-9PM. We currently cover over 10k cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Vehicle Engine Mechanical Inspection reviews

Excellent Rating


YourMechanic Vehicle Engine Mechanical Inspection Service

Average Rating

4.9/5

Number of Reviews

133,914

Rating Summary
125,134
4,880
972
679
2,249
125,134
4,880
972
679
2,249

Jamahl

19 years of experience
830 reviews
Jamahl
19 years of experience
Chrysler 200 - Spark Plugs - Orlando, Florida
Good mechanic 
Saturn Aura - Starter - Orlando, Florida
Did a good job with my car

Ricardo

13 years of experience
339 reviews
Ricardo
13 years of experience
Porsche Cayenne - 30,000 Miles Maintenance Service - Los Angeles, California
He was very thorough and knowledgeable. I will call again.
Ford Mustang - Pre-purchase Car Inspection - Norwalk, California
Great service! Everything done in a timely professional manner

Raymond

36 years of experience
171 reviews
Raymond
36 years of experience
Cadillac Brougham - Vehicle Engine Mechanical - Las Vegas, Nevada
Talent and passion for what you do in any field is critical, Raymond seems to have both. I have dealt with many Mechanics in my day Raymond is one of the best. Thank you sir.

Gary

34 years of experience
91 reviews
Gary
34 years of experience
Lexus GX470 - Oil/Fluid Leak - Roswell, Georgia
Gary is awesome. Very thorough and knowledgeable!

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE