What Are the Causes of Engine Stalling and Shaking at Idle Speed?
4 Answers
The causes of engine stalling and shaking at idle speed are: 1. Dirty throttle body; 2. Excessive carbon buildup in fuel injectors; 3. Faulty engine mounts; 4. Aging engine components; 5. Ignition system issues. Solutions for engine stalling and shaking at idle speed: 1. Clean the throttle body; 2. Clean the fuel system; 3. Remove carbon deposits from the engine and fuel injectors; 4. Check if spark plugs have excessive carbon buildup and replace them if necessary; 5. Replace aged components. Idle speed refers to the engine running without load, overcoming internal friction resistance without delivering power output, maintaining the minimum stable operating RPM.
I just encountered this situation last month! While idling at a red light, the steering wheel shook like a massage chair, then suddenly 'poof' – the engine stalled. The mechanic opened up the engine, and wow, carbon buildup had completely clogged the fuel injectors. The throttle body was so caked with sludge you could mold it like playdough, and the spark plug electrodes were burnt to a crisp. They recommended cleaning the throttle body and intake manifold. If that doesn’t work, you might need to check the engine mounts. My old car became rock-solid after replacing the mounts – no more idle disco moves. Oh, and if it shakes even worse during cold starts, chances are the coolant temperature sensor has called it quits.
It depends on the rhythm of the shaking. If it fluctuates like gasping for air, it's most likely an air intake system leak. I've seen cracked vacuum tubes—spraying hairspray on the tube walls can help locate the leak. If there's a rhythmic shake with a 'ticking' sound, it's probably a misfiring cylinder—unplug the ignition coil connectors one by one to test; the one that doesn't worsen the shaking when unplugged is the faulty cylinder. Last time my car had a misfire in cylinder 1, it turned out to be a corroded ignition coil connector. Don't overlook low fuel levels either—if the fuel pump can't draw fuel, it can cause shaking and stalling, especially on inclines.
Just helped a neighbor with this issue. First check three basics: replace spark plugs if gap exceeds 1mm, swap out aging ignition coils with unstable output, and discard clogged air filters. Measure fuel pressure with a mechanical gauge - if below 250kPa, inspect fuel pump and filter. Reading fault codes via OBD is crucial - oxygen sensor errors will disrupt air-fuel ratio. Remember one case where the crankcase vent valve stuck shut, trapping all exhaust gases in the engine like driving while holding your breath - no wonder it was shaking!
