What Causes Jerking When Accelerating in a BMW 5 Series?
4 Answers
Jerking when accelerating in a BMW 5 Series is caused by the engine failing to reach its optimal power output. When the engine cannot deliver optimal power under increased load, the vehicle may experience jerking sensations. This condition could result from insufficient ignition energy due to faulty ignition coils or weak spark plug sparks, leading to inadequate power delivery. Below are explanations regarding jerking in the BMW 5 Series: 1. Clogged Fuel System: Clean the fuel system, injectors, fuel lines, and fuel pipes. 2. Normal Jerking During Automatic Transmission Vehicle Start: When attempting rapid acceleration, pressing the accelerator pedal deeply causes the automatic transmission to downshift and increase engine RPM. Upon reaching a certain RPM, the transmission upshifts, resulting in a noticeable RPM drop and consequent jerking sensation. This is more common in automatic transmissions with fewer gears, such as 4-speed automatics. For smoother driving after starting an automatic transmission vehicle, gently pressing the accelerator pedal at appropriate times prompts the transmission to upshift with minimal jerking. For better acceleration performance, deeper pedal presses cause the transmission to upshift at higher speeds, resulting in more noticeable gearshift jerking.
I've been driving a BMW 5 Series for several years, and the jerking when accelerating is really annoying. Usually, the issue lies in the ignition system, such as aging spark plugs failing to ignite the fuel properly, causing engine misfires and resulting in hesitation during acceleration. Sometimes, it's a fuel system problem, like clogged fuel injectors leading to uneven fuel spray, or a dirty air flow sensor causing insufficient air intake. Transmission-related factors can also be involved; if the electronic control unit in BMW's automatic transmission misjudges the RPM, gear shifts can become abrupt. I recommend checking the spark plugs and fuel filter first. BMW models are sensitive to fuel quality, so avoid using low-grade fuel. Regular professional diagnostics are crucial, as neglecting minor issues can harm engine longevity and fuel efficiency. Safety comes first—severe jerking can lead to loss of control, so address it promptly.
My BMW 5 Series ran smoothly when new, but later developed jerks during acceleration, like being suddenly yanked. After troubleshooting, I found the transmission is often the culprit - BMW's 8-speed automatic can become sluggish without software updates or with worn clutch components. Faulty ignition coils are also common, causing unstable voltage that disrupts combustion. I've DIY-replaced the air filter myself (simple and cost-effective) since clogged intake causes issues. Sensor problems like throttle position misreporting can delay throttle response too. Don't neglect maintenance cycles - inspect electrical systems at least biennially. BMWs are precision machines; having a professional scan fault codes (affordable) prevents major repairs and ensures peace of mind while driving.
The BMW 5 Series' jerky acceleration is really annoying, but it's mostly minor issues: the spark plugs might be burnt out and failing to ignite the fuel; or the fuel line could be clogged, causing poor fuel injection; or even the transmission computer might be acting up. I've experienced it myself, and it's more noticeable during cold starts—cleaning the throttle body fixed it. Don't delay; check the fuses and plug connections. Regular maintenance with good-quality oil can prevent these problems, otherwise, fuel consumption will skyrocket.
