What Causes Severe Engine Vibration During Startup
2 Answers
Here are the reasons for severe engine vibration during startup: 1. Damaged spark plugs, where the wear of the spark plug electrode gap leads to insufficient spark ignition, resulting in incomplete combustion of the air-fuel mixture; 2. Poor quality gasoline, which causes poor atomization effect of the fuel injector, leading to incomplete combustion of the mixture in the cylinder; 3. Dirty throttle body and excessive carbon buildup on the fuel injector; 4. Abnormal fuel pump supply pressure or incorrect and malfunctioning intake pressure sensor readings. Additional information: The function of the engine is to convert thermal energy into mechanical energy by expanding gas after combustion in a sealed cylinder, pushing the piston to do work, thereby providing power to the vehicle.
Last time my old car shook like a massage chair when starting up, and it turned out the ignition coil was dead—one cylinder completely stopped working. This kind of shaking usually comes from a misfiring cylinder. If the spark plugs haven’t been changed in seven or eight years, they should definitely be checked first, especially during cold starts when it’s most noticeable. Engine oil viscosity being too high or worn-out engine mounts can also make the steering wheel shake uncontrollably, so keep an eye on whether the check engine light is on. Once at the repair shop, I saw a mechanic use a computer to read the data stream and found that the third cylinder wasn’t injecting fuel at all—the fuel injector was completely clogged. Now, whenever the car shakes badly at startup, I turn it off and try again. If it still shakes, I call a tow truck immediately—after all, you don’t want to damage the catalytic converter and end up spending even more money.
