What Causes Engine Shaking During Ignition?
2 Answers
The causes of engine shaking during ignition are: 1. Dirty throttle body or excessive carbon buildup in fuel injectors; 2. Worn-out or loose engine mounts; 3. Engine misfire (cylinder not firing); 4. Intake system malfunction; 5. Poor fuel injector atomization or clogging; 6. Additional air valve not opening or insufficient opening during cold starts. Vehicle maintenance methods include: 1. Regular car washing and waxing; 2. Timely replacement of engine oil, oil filter, cabin air filter, and engine air filter; 3. Monitoring tire pressure changes while driving; 4. Periodic checks for coolant, brake fluid levels and color changes; 5. Prompt repair of minor vehicle issues.
A few days ago, my car shook violently when starting. At first, I thought it was just a cold weather issue, but later I realized there could be several reasons for the shaking. The most common one is aging spark plugs—over time, their sparking efficiency drops, leading to rough ignition and the engine running unevenly. Another issue could be a clogged fuel system; if the fuel injectors are carbon-fouled and can't spray fuel properly, combustion becomes uneven, causing the car to shake like a small boat when starting. Weak ignition coils or a low battery can also be culprits, as insufficient power supply makes the startup unstable. In my case, it turned out to be a dirty throttle body causing insufficient air intake, and the problem improved after cleaning it. If you encounter such symptoms, don’t ignore them—get your car checked at a repair shop promptly. Otherwise, prolonged issues can lead to increased fuel consumption and even engine damage.
