What causes the BMW X5 to shake at idle?
2 Answers
BMW X5 shaking at idle can be caused by: 1. Severe engine carbon buildup: The most common cause of car shaking is a dirty throttle body or excessive carbon deposits on the fuel injectors. After starting, gasoline adsorbed on the carbon deposits will be sucked into the cylinder by the engine's vacuum suction for combustion, enriching the air-fuel mixture. This causes the engine's combustible mixture to fluctuate between lean and rich, resulting in idle shaking after a cold start. The lower the temperature, the more fuel is required for a cold start, and the presence of carbon deposits will significantly affect whether the cold start proceeds smoothly. Solution: Clean the fuel system and check if the idle air control valve has carbon buildup, which should be thoroughly cleaned. 2. Ignition system issues: Check the condition of the spark plugs, high-voltage wires, and ignition coils. Poor performance of the ignition system or inadequate spark plug firing can also lead to such symptoms. Solution: Check if the spark plugs have excessive carbon buildup and replace them if necessary. 3. Unstable fuel pressure: If you have already cleaned the engine carbon deposits, throttle body, replaced gaskets and spark plugs, but still experience shaking at idle, it is recommended to visit a 4S shop to check the fuel supply pressure and the intake pressure sensor. Abnormal fuel pump pressure or incorrect readings and poor performance of the intake pressure sensor can cause the car to shake. Solution: Check the fuel pressure and replace components if necessary.
Dude, your BMW X5 is shaking like a tractor? Probably a few common issues. I just fixed one of the same model, most likely the engine mounts are shot—when they age, they get as soft as chewing gum, and the engine isn't secured properly, causing it to vibrate. Also, the BMW N55/B58 engines are notorious for carbon buildup on the back of the throttle body; when it gets too thick, it even restricts idle airflow. If it shakes more with the AC on, check the spark plugs and ignition coils right away—cars with lots of electronics are picky about this. While you're at it, clean the mass airflow sensor; if it's dirty, the ECU will mess up the fuel mixture. Lastly, I’d recommend filling up with Sinopec or PetroChina 95-octane gas—poor-quality fuel from small gas stations can also cause shaking.
