What Causes the BMW N55 Engine to Jerk at Idle?
2 Answers
BMW N55 engine idle jerking may be caused by air leaks in the vehicle or ignition system malfunctions. Below is detailed information about the BMW N55: 1. Overview: BMW automobiles refer to vehicles produced by Bayerische Motoren Werke AG (abbreviated as BMW). The main series models include the 1, 2, 3, 4, 5, 6, 7, and 8 Series. 2. Logo: The BMW emblem features a double-circle design with the "BMW" inscription above the double rings. The entire logo resembles the blue sky, white clouds, and a continuously rotating propeller, symbolizing the company's long history and its consistent mission and objectives.
I've been repairing BMWs for over a decade, and N55 idle shaking is very common. The most frequent cause is intake system leaks, especially the valve cover breather hose and turbo intake pipe - these rubber components tend to harden and crack after about five years. Next is the ignition system - factory spark plugs with over 30,000 km will misfire as the gap widens, and oxidized coil pack connectors can also cause cylinder misfire shaking. Then there's carbon buildup - direct injection engines get intake valve clogging from deposits, causing unstable air-fuel mixture. Just last week I fixed one where the tachometer needle was jumping half a division at idle, with the scanner showing multiple cylinder misfires - replacing the valve cover breather hose and spark plugs solved it. Never overlook vacuum leaks - any rubber hose that squeaks when pinched should be replaced.
