What Causes Engine Misfire and Car Vibration?

[StBrayden]

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.