What Causes a Car to Stall Easily at Idle?
2 Answers
The reasons why a car stalls easily at idle are: 1. Throttle blockage, carbon buildup, or abnormal opening; 2. Carbon buildup or blockage in the fuel injectors; 3. Spark plugs being burnt or damaged; 4. Use of low-quality gasoline, leading to fuel pump blockage; 5. Incomplete combustion of the air-fuel mixture in the cylinder. Solutions to prevent stalling at idle include: 1. Regularly cleaning the throttle; 2. Periodically cleaning the fuel injectors to prevent carbon buildup; 3. Replacing spark plugs; 4. Using gasoline from reputable gas stations. The reason a car stalls at idle is: After the engine starts, it runs well from low to high speeds, but stalls immediately when the accelerator pedal is released or first becomes unstable and then stalls.
I've encountered this situation quite a few times. The most common cause of stalling at idle is a dirty throttle body getting stuck - a good cleaning usually fixes it. It could also be an issue with the idle air control valve, which manages the air intake at low engine speeds. Another possibility is a faulty mass airflow sensor or manifold absolute pressure sensor, causing the ECU to miscalculate fuel injection. Excessive spark plug carbon buildup causing misfires or an unstable fuel pump cutting supply suddenly can also be the culprit. For older vehicles, vacuum leaks leading to overly lean air-fuel mixture might be the reason. Last time my car had this issue, it was the PCV valve leaking - replacing it solved the problem. You can try revving the engine in neutral a few times to see if it improves.
