Why Does the Engine Stall at Idle?
3 Answers
Here are the reasons why the engine stalls at idle: 1. Circuit failure: The engine stalls due to low-voltage power failure while driving. A short circuit in the low-voltage circuit causes intermittent stalling. Check the vehicle's low-voltage circuit, ignition and starter switch, and fuse box. 2. Component failure: Usually related to the ignition coil, capacitor, or electronic ignition module. The engine may start initially but stall after a while, then restart and stall again. 3. Fuel system failure: Damaged fuel pump, cracked fuel line, clogged carburetor fuel inlet, or empty fuel tank. In such cases, the car is difficult to restart. 4. Ignition system: Engine overheating or issues with the anti-explosion system can also cause stalling.
I've noticed that when a car suddenly stalls at idle, it's quite a common issue, mainly due to excessive carbon buildup in the throttle body, which blocks the air passage, causing the engine to suffocate. It could also be an unstable fuel supply from the fuel pump, where insufficient pressure at low speeds leads to stalling. If the spark plugs are worn or dirty, the ignition becomes weak, making it prone to misfiring at idle. Additionally, sensors like the idle control valve or throttle position sensor, if faulty, can confuse the car's computer about how to adjust the engine speed, resulting in a stall. I've dealt with this problem before; cleaning the throttle body and checking the fuel filter often helps, but for severe cases, it's best to visit a professional repair shop because stalling at traffic lights is too dangerous. Other minor culprits could be a clogged air filter or loose electrical wiring.
Having driven for many years, I've encountered engine stalling at idle several times, especially in older cars. The usual culprit is severe carbon buildup in the throttle body, preventing air intake and causing the engine to shut down. Fuel system issues also play a role, such as a weak fuel pump or insufficient fuel supply at idle, exacerbated by a dirty filter. On the ignition side, worn spark plugs or failing ignition coils can make the engine prone to stalling. I believe faulty sensors are also to blame; once the idle control valve gets dirty, idle RPM drops, leading to stalling. Cleaning the throttle body yourself can solve some issues, but if it happens frequently, the entire fuel and air systems need inspection. Don't overlook battery or wiring problems—they might be causing trouble too.
