What Causes Engine Misfire and Car Vibration?
3 Answers
Engine misfire and car vibration can be caused by: 1. Severe engine carbon deposits - During cold starts, the gasoline sprayed by the fuel injectors gets largely absorbed by these deposits, resulting in an overly lean air-fuel mixture that makes starting difficult and causes idle vibration after cold starts; 2. Check the working condition of spark plugs, high-voltage wires, and ignition coils - Poor performance of the ignition system or weak spark plug firing can also lead to such symptoms; 3. If you've already cleaned engine carbon deposits, washed the throttle body, replaced gaskets and spark plugs but still experience body vibration, it's recommended to visit a 4S shop to check fuel supply pressure and intake pressure sensors for proper operation.
Engine shaking usually indicates that the engine is running unevenly. The most common cause is an issue with the ignition system, such as aging spark plugs or severe carbon buildup, leading to delayed or interrupted ignition and incomplete combustion, which causes shaking. The fuel system may also be faulty—clogged fuel injectors or insufficient fuel pump pressure can disrupt the air-fuel mixture, making the engine sputter. Additionally, a faulty oxygen sensor or a vacuum leak can affect the air intake, leading to incorrect air-fuel ratios. Furthermore, if the engine mounts are damaged or loose, the entire machine may wobble incessantly. Minor shaking can escalate into major issues like cylinder misfires or catalytic converter failure, increasing fuel consumption and damaging the engine. It is recommended to perform regular maintenance, including checking and cleaning spark plugs and fuel injectors. If shaking is detected, seek professional repair promptly to avoid safety hazards and ensure effective repairs.
I've experienced a similar issue with my own car—it shakes like it's shivering. The main culprit was the spark plugs needing replacement; over time, carbon buildup causes unstable ignition. If the fuel injectors get dirty and clogged, uneven fuel supply makes the engine stall and shake. A vacuum hose leak introduces too much air, making the air-fuel mixture too lean, which also causes problems. Ignoring these minor issues can lead to skyrocketing fuel consumption and even trigger ECU error codes—once the check engine light comes on, it's a real headache. It's best to stop and check for unusual noises or smells instead of forcing it to run, then take it straight to a repair shop for diagnosis to avoid costly repairs. Using quality fuel and additives to clean the system regularly can prevent these issues, reducing shaking and making driving smoother.
