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Why your Car may Idle in Park and Neutral

A car can experience high idling in neutral or park for several reasons. This post focuses on what high idle is, and four major reasons your car to idle high in park and neutral.

What is High Idle?

Car idle is commonly used to refer to a vehicle whose engine is on but not in motion. A car can idle at the stoplight, waiting for it to turn green so that you can resume driving. Also, the vehicle can idle when the engine is still on but in the park position.

High idle is when a car produces extreme movement, noise or shaking from the engine every time it’s idle. A typical vehicle engine should not make a noise or shake that the driver and passengers can hear. So when you hear some sounds and movement from the engine, a problem must be solved.

Besides the revving sound, the other sign of car idling is more fuel consumption when driving the same distance. If the car engine is on, the process of burning fuel will continue. An engine in its perfect state will always burn small amounts of fuel in the idle state, either in a park or neutral. But a vehicle that is experiencing high idling tends to burn more fuel. The burn of excess fuel results from extra power demand on the engine, even when the car is not in a motion state.

Causes for Car Idling High in Park and Neutral

Here are the four reasons for a car to high idle in park and neutral.

Damaged control valve

Control valves need to be in perfect working condition so that there can be a continuous flow of air into the engine. A problem at the valves will lead to the prevention of airflow. In this case, the fuel will not enter the combustion chamber. The engine will stall when there is a loss of fuel and air.

Blown fuse

Whenever a fuse blows in the engine, it impacts the IAC motor negatively, making it malfunction. If the IAC motor is not working properly, the engine will idle at a higher speed while in parking and neutral positions.

Malfunctioning of the coolant sensor

When a coolant sensor has a problem, it wrongly detects the engine temperature. It may detect the engine as running hot when it is cold and vice versa. Poor detection will increase the engine’s fuel burning rate and lead to stalling of the vehicle while driving. Rough idling and shaking are problems that are also brought out by the failure of the coolant sensor.

Vacuum leak

A vacuum leak is one of the severe scenarios. Inside the engine is an oxygen sensor. When it detects more oxygen coming into the internal combustion chamber, the engine will be forced to cater for the additional air with extra fuel. As a result, there will be more than the required air and fuel in the engine, leading to high idle in a park or neutral state.

Effects of High Idling in Park and Neutral

A car idling too high in park and neutral position may damage the engine and other significant components. Reduction in fuel efficiency and increased emissions is another effect of high idling.

Ways of Fixing a Car Idling High in Park

Fixing high idle cases in a car will require the labor and work of a reliable mechanic. The following is an overview of how one can fix these problems.

The Control Valve

Possibly, the control valve may contain some grime, dirt or rust that may be clogging it up. Cleaning the valves will lead to unrestricted airflow, and your car’s engine will be free from stalling.

Blown Fuse

The remedy for a faulty or blown fuse is replacing it with a new one. Through replacement, the IAC motor will function properly.

The Faulty Coolant Sensor

If the coolant sensor is not functioning well, you will have to incur the cost of replacing it. Once it has been replaced, the high idle problem will be solved, and the fuel economy will improve.

The Vacuum Leak

The leaking problem can be solved through patching to prevent additional air from getting into the engine. When the engine doesn’t receive extra air, the sensors will not have to force additional fuel into the engine. The internal combustion chamber will function in the required way.

Bottom Line

The perfect solution to prevent a car from high idling while in a park or neutral position is cleaning the control valves, repairing a vacuum leak and replacing the damaged coolant.

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