Why does the car idle shake and then stall?
3 Answers
The reasons why the car idles and shakes before stalling: 1. Excessive carbon deposits cause pre-ignition and detonation, shortening the engine's service life and significantly reducing its power and fuel economy; 2. Carbon deposits on the valve and its seat ring working surfaces cause the valve to not close tightly, leading to air leakage, difficulty in starting the engine, lack of power, and other adverse phenomena such as valve burn-out; 3. Carbon deposits and gum formation on the valve guide and valve stem accelerate the wear between the valve stem and valve guide, and may even cause the valve stem to stick or seize in the valve guide, resulting in valve sticking faults; 4. Excessive carbon deposits on the spark plug can cause spark plug leakage, failure to work, engine shaking, and other faults.
Oh, as an experienced driver, I've encountered the issue of engine stalling after idling vibration several times, and there are many possible causes. It could be due to aging spark plugs failing to ignite, or the spark plugs themselves being faulty - once the ignition system malfunctions, the engine shakes like it's drunk. A weak fuel pump causing insufficient fuel supply can also lead to this; I once had a car with this exact problem that would violently shake and stall at low speeds. A dirty throttle body blocking the air intake passage is another common culprit, as accumulated grime eventually makes idle unstable. An overly dirty air filter affecting airflow requires regular replacement. Faulty sensors like oxygen sensors sending incorrect data can cause the ECU to make wrong control decisions. For safety's sake, get it checked at a repair shop immediately - don't delay and risk the problem worsening until you're stranded with a breakdown on the road.
The car idles roughly and then stalls, which is a typical fault often rooted in the ignition or fuel system. You can check some basic items yourself: Open the hood and inspect if the air filter is clogged or blackened, affecting air intake efficiency. The condition of the spark plugs is crucial—pull one out to check for electrode wear or carbon buildup. A clogged fuel filter can restrict fuel flow, leading to increased shaking before stalling. A stuck idle control valve can cause unstable idling—try cleaning it. Vacuum leaks are also a common cause; listen for any abnormal hissing sounds. If initial checks yield no results, use a diagnostic tool to read codes and check for sensor abnormalities, such as a faulty mass airflow sensor. Don’t underestimate the need for timely repairs to avoid driving risks.
