9 Ways to Fix High Idle After Cleaning Throttle Body

Throttle body cleaning is an excellent preventative practice for car maintenance. It also enables smoother air movement with less turbulence and aids in engine drivability.

Cleaning the throttle bodies could sometimes result in the idle being thrown up. It affects your car’s idle speed as it is under control by the computer through the throttle body motor assembly.

In this article, we will share with you how to fix the high idle after cleaning the throttle body.

Causes of high idle after cleaning throttle body

Vacuum leak

Mass airflow sensor accurately measures the air quantity that is going into the engine inside the throttle body. A vacuum leak could occur when the throttle body permits more air into the machine, and the computer is compensating by adding more fuel.

It makes the idle relearn when you place the vehicle in drive and enable it to go down with all accessories off for about two to three minutes. Due to the excess air intake, the data will not be in line with ECU-measured airflow resulting in the ‘Check Engine light being triggered.

After the vacuum leak occurs, a lean fuel-air mixture results in erratic idling and lacklustre slow performance. It is relatively cheap and easy to mend and should be fixed for the engine to perform optimally.

Torn intake hose

Air intake hoses send measured air to the inner combustion engine intake manifold. Once they are torn, it could lead to high idling. It is because of the air flowing past the throttle.

The leak could result in a lean or combustion mixture with an excess ratio of fuel that can cause engine stalling or rough idling. Rough idling calls for the replacement of the air intake hose.

When debris enters the air intake hose via openings or leaks, it causes numerous engine problems like poor performance and stalling. It can also enter the engine and result in severe damage.

A sucking or whistling noise could signify air being sucked via the hose leak.

Debris in the throttle bore

Debris in the throttle bore causes unsmooth movement of the plate and causes rough idling, sluggish or jumpy acceleration, stalling, and poor fuel economy. It also results in;

1. Grime buildup

It prevents the car from pulling in enough fuel, leading to interruption of air and fuel flow, resulting in an imbalance in the flow.

2. Electrical problems

They can cause intermittent or false information to be communicated to the car’s computer making faulty corrections to the air-fuel mixture.
It can also result in a ‘limp-home mode switch with reduced power to the car’s engine regardless of how hard you press the peddle.

Computer readjusting

When you clean the throttle body, it physically resets the system meaning your car’s computer has to recalibrate, causing extra fuel to be added to the system and your idle raises.

How to fix high idle after cleaning throttle body

Giving computer time to relearn itself

You should note that the idle shall be high at first until the computer relearns it again.

The computer will relearn the idle when you place the vehicle in drive and permit the idle to go down with all accessories off for about two to three minutes. Cars have an adaptive system that learns our driving behavior and changes tables to match.

After relearning the idle, turn on your a/c with a blower in a high position for three minutes.

Remove the throttle body and seriously clean it

It is in the case where there is debris in the throttle body. Cleaning it thoroughly on the front and rear of the bore should fix the problem.

After the cleaning, the computer should identify the throttle plate’s location and correct the idle after driving for a while.

In case the problem persists, the throttle sensor or motor location may be damaged during cleaning. It happens when the throttle plate is opened and closed over and over again faster. It results in a necessary recalibration and calls for a check-up by a certified mechanic.

Using a computer scan tool

It is used to monitor the inputs of the throttle position sensor and motor to see what is going on. It checks throttle activity and position to identify the damage and replacements needed to fix the great idling problem.

Resetting the electronic throttle control manually

It is done by turning the ignition switch on and waiting for three seconds. After the three seconds, immediately press and release five times within five seconds. Wait for seven seconds and press the accelerator pedal fully and hold for about 20 seconds until the check engine light seizes blinking and stays on.

Correcting the Throttle Position Sensor

An incorrectly positioned throttle position sensor result in high idling. A correct idle and normal acceleration can be brought by unplugging its connector and adjusting it correctly.

Reprogram the throttle body after cleaning

Check the throttle cable

Ensure the throttle body valve reaches the rest position.

Check the vacuum hose

Ensure that the vacuum hose that links to the throttle body is not leaking.

Fix the idle air screw atop the throttle body

Use a flat-bladed screwdriver to fix the idle air screw atop the throttle body. Screwing it in reduces the idle speed while screwing it out increases it.


Cleaning the throttle body enables smooth running of the car. If done incorrectly, it causes high idling, which is caused by vacuum leaking, torn intake horse, debris in the throttle bore, and computer readjusting. Each of the problems has its effects that have homemade solutions, while some require certified mechanics. You ought to fix the issues immediately you notice them in avoidance of worse and more expensive situations.

Several ways to improve the problems are; Giving the computer time to relearn itself, removing the throttle body and thoroughly cleaning it, using a computer scan tool. Checking the throttle position sensor, throttle cable, vacuum hose that they are correctly located, ensuring throttle plates are closed, the throttle body moves freely, and the correct time at the cam, crank, and distributor. With more experience, you will be able to clean yours with less or no damage.

  • Eric Williams

    I'm the founder of Daily Car Tips. I wrote articles in the automotive industry for more than 10 years, published in USA and Europe. I love sharing my knowledge and insights with fellow enthusiasts. Join me on this journey as we explore the exciting world of cars together!

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