BMW 116i (F20) - Vehicle jerking at full load

In the above-mentioned vehicle type, the vehicle may jerk at full load or briefly cut out power transmission – especially from fourth gear onwards. The engine malfunction indicator light remains off and no relevant entries are stored in the engine control unit fault memory.

If the above-mentioned fault pattern sounds familiar, and if no definite faults have been identified in the periphery of the affected systems during troubleshooting, pay special attention to the ignition system. The ignition coils may cause sporadic misfiring when under load, which are not clearly identified by the control unit and therefore do not trigger a fault memory entry. The resulting incomplete combustion manifests itself as a jerky power cut-outs while driving.

For troubleshooting, check the ignition system parameters using a suitable diagnostic unit during a test drive. If the live data in the control unit is abnormal in terms of misfiring under load, remove the spark plugs as per manufacturer's instructions and visually check them for faults. If there are no abnormalities on the spark plugs, replace the ignition coils at one position at a time. Then repeat the test drive and re-analyse the parameters to narrow down the affected component.

If misfiring re-occurs on a different cylinder during the repeat test drive, replacing the affected ignition coil may eliminate the issue.

Once the cause of the fault has been rectified, delete the fault memory and then go for a test drive.

For your own safety and the safety of other road users, test and trial drives must always be carried out with a second person (driver) present.

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