Why Does My Car Rev High When I Start It


Does your car rev high when you start it? Is your car surging when it idles? Or does it stall out when you come to a stop? The ideal car rev on a cold engine should be below 1000 RPMs (around 800 RPMs). If your car rev above 1000 RPMs when you start it, that is something that you should look into. I will show you how to diagnose and fix this issue on your own, without any prior mechanic experience.

Why Does My Car Rev High When I Start It

Why does my car rev high when I start it? Your car could rev high when you start it if you have a dirty throttle plate, or a dirty idle air control valve. The throttle body controls the amount of air that enters the engine and when it gets clogged, the fuel to air mixture is thrown out of balance and your car will rev high when you start it. The idle air control valve controls the amount of air needed to maintain a steady engine idle.

Why Does My Car Rev High and How To Fix It

If your car revs high when you start it, which is usually above 1000 RPMs, you could have a dirty throttle body or a dirty air idle control valve. Both the throttle body and the air idle control valve control the amount of air that gets into the engine. The throttle body makes sure more air gets into the engine when you press the gas pedal, while the air idle control valve is in charge of suppling the engine with enough air to keep a steady idle. If the throttle body or the air idle control valve is dirty, that can result in high revs when you start your car.

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Here is how to clean your throttle body and the air idle control valve:

1. Gather the cleaning supplies

Why Does My Car Rev High When I Start It

In order to clean your throttle body and the air idle control valve, you will need a throttle body and air intake cleaner. The one that I use is made by CRC and I got it from amazon.com. Then, you will need a microfiber towel to wipe the throttle body and the air idle control valve.

2. Remove the air filter housing

Why Does My Car Rev High When I Start It

The air filter housing is easy to locate and remove. It is usually found on the right side of the engine and is secured with clamps. Unsnap the air filter housing and pull it up.

3. Remove the ductwork

After you remove the air filter housing, you will have to remove the ductwork that goes from the air filter into the throttle body. Usually, the ductwork is secured with screws and clamps. Remove the screws and pull the assembly out of the way. At this point, you should have an exposed throttle body.

4. Clean the throttle body

Depending on your car, you can have one or two throttle bodies. Nevertheless, the cleaning process is the same. Open the throttle body by pressing the gas pedal or manually by pulling the throttle body line and spray the throttle body cleaner. Make sure to spray the top, bottom, and sides. Then, grab a clean microfiber towel and wipe the inside of the throttle body. If the throttle body is very dirty, repeat the same process.

5. Clean the air idle control valve

The air idle control valve is located on top of the throttle body. The air idle control valve is usually secured with screws. Remove the screws that hold it in place and then take the assembly off to clean the inside of it. Spray the air idle control valve with the throttle body cleaner and then wipe it with a clean microfiber towel.

6. Let it dry for half an hour

It is a good idea to just leave your car as it is to dry for half an hour before you put it back together. Otherwise, the car will be full of cleaner and be very hard to start.

7. Reinstall the parts

Reinstall the air idle control valve assembly. Then, attach the ductwork and secure it with the clamps. Finally, reattach the air filter housing and snap it.

8. Start your car

Start your car and let it run for 20 minutes. The car will probably rev high in the beginning because of the throttle body spray cleaner. You might also notice smoke coming out of the exhaust. But, don’t worry. It will all be gone after 20-30 minutes. Your car should now rev normally under 1000 RPMs.

What RPM Should a Car Start At?

What RPM should a car start at? Cars with up to a 2.0-liter engine should start with 500 to 800 RPMs. Cars with engines above 2.0-liter engines should start with 550 to 750 RPMs. Usually, for most engines it is perfectly fine to start with 600 to 1000 RPMs. As the engine warms up, the RPMs should drop for at least a 100 RPMs from the original starting RPMs.

The RPM stands for revolutions per minute. When you start your car, especially in cold winter, the engine RPMs will be higher than usual. That’s because the engine works even harder to get to the optimal working temperature. The RPMs should go down as the engine warms up. If your car has a rough idle even when the engine reaches the optimal temperature, you might have a dirty throttle body or an air idle control valve.

What RPM Should My Car Be At 60mph?

What RPM should my car be at 60 mph? Your car RPMs while driving at 60mph should be between 2400 and 2600 RPMs in 5th gear. This is also known as the cruising speed and at this speed, gear, and RPMs, your car is the most fuel-efficient.

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