The throttle body is an essential component of any gasoline-powered engine.
It regulates the air entering the engine, allowing it to maintain a consistent idle speed and performance.
The throttle body malfunctions can lead to six bad symptoms: engine stalling or misfiring, poor acceleration, idling issues, reduced fuel economy, check engine light, cruise control not working, and harsh shifting in automatics.
These faults are most prominent on modern engines with drive-by-wire throttle bodies where the vehicle can’t give the right amount of throttle opening as the driver demands.
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7 Bad Throttle Body Symptoms
Here are seven of the most common bad throttle body symptoms:
Engine Stalling or Misfires
A bad throttle body can cause the engine to stall or misfire.
When the throttle body is not working correctly, it can cause a disruption in the air-fuel mixture that the engine needs to run, as the ECU can’t control the throttle opening as the driver demands it.
This can lead to rough idling or even complete engine shutdown.
Another symptom of a bad throttle body is poor acceleration.
If the throttle body is not functioning correctly and can’t open all the way or hesitates, it may not allow enough air into the engine, resulting in sluggish acceleration.
A bad throttle body can also cause the engine’s idle speed issues.
The engine may idle too high or too low and fluctuate between the two.
This is most prominent in drive-by-wire systems as the throttle body controls the idle speed with the throttle body opening, and if it can’t control it, the vehicle will fail to idle.
Reduced Fuel Efficiency
If the throttle body is not working correctly, it can cause the engine to burn more fuel than necessary.
This can lead to reduced fuel efficiency, which can be costly in the long run.
A good example is when the throttle body is very abrupt with its movement and can’t do small movements; thus, the car will constantly fluctuate in road speed as you try to adjust for it.
Check Engine Light
A malfunctioning throttle body can also trigger the check engine light to come on.
This is because the engine’s computer detects a problem with the throttle body’s operation and warns the driver that something is wrong.
This will also generate a code you can read with an OBD-2 scanner.
Cruise Control Not Working
Cruise control relies on the throttle body to maintain a constant speed, so if the throttle body is not functioning correctly, the cruise control will not work properly.
When the driver engages cruise control, the system sends a signal to the engine control module (ECM), which sends a signal to the throttle body to maintain a specific speed.
If the throttle body is malfunctioning, it may not receive the correct signal from the ECM, causing the cruise control to either not engage or disengage unexpectedly.
A bad throttle body can cause harsh shifting in vehicles with an automatic transmission.
This is because the engine’s computer relies on input from the throttle body to determine when to shift gears.
If the throttle body is not functioning correctly, it can cause the transmission to shift too early or too late, resulting in rough shifting.
Final Thoughts On Bad Throttle Body Symptoms
If you experience these symptoms, having your vehicle inspected by a professional mechanic is essential.
A certified technician can diagnose the problem and recommend the appropriate repairs.
A bad throttle body can be repaired or replaced, restoring proper engine performance.
Here is an excellent video of 1A Auto that will take you step by step to clean or replace your throttle body by yourself:
In conclusion, a bad throttle body can cause several bad symptoms impacting the engine’s performance and fuel efficiency.
Hopefully, you found this article helpful in diagnosing if your vehicle has a bad throttle body.
What Happens When The Throttle Body Goes Bad?
When the throttle body goes bad, it can cause several issues that can negatively impact the engine’s performance and drivability.
The throttle body regulates the air entering the engine, allowing it to maintain a consistent idle speed and performance.
How Do I Know If My Throttle Body Needs To Be Replaced?
Your throttle body will need replacing if you experience your engine stalling or misfiring, poor acceleration, idling issues, reduced fuel economy, check engine light, cruise control not working, and harsh shifting in automatics.
Can A Bad Throttle Body Mess Up Your Engine?
While it does not have very immediate effects on the engine, it can cause problems in the long run.
A good example is irregular or poor acceleration which can cause the engine to shake and cause unwanted vibrations that can damage the engine over a long period and even damage your engine mounts.