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Persistent Cylinder 4 Misfire in BMW 5 Series - Injector Replacement Ineffective

Loss of engine power

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Check engine light on

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Shaking while idling

I'm experiencing a persistent issue with my BMW 5 Series where the check engine light is on, there's a loss of engine power, and the car shakes while idling. The problem seems to be a misfire in cylinder 4 of the N63 engine, even after replacing the old injector a few months ago. Could this be due to air in the combustion process or a clogged intake valve from carbon buildup? Any advice or suggestions would be greatly appreciated.

3 comment(s)


CarlyMechanic

Start by checking the ignition coil and spark plug for cylinder 4, as these are common causes of misfires. If they are faulty, replacing them might resolve the issue. Let me know how it goes or if you have any further questions.

Butter (Author)

@CarlyMechanic

Start by checking the ignition coil and spark plug for cylinder 4, as these are common causes of misfires. If they are faulty, replacing them might resolve the issue. Let me know how it goes or if you have any further questions.

Sparks and coils were replaced at the same time. Checked the spark plugs and they looked to be operating just like the others I checked. Its weird, when I start the car there’s no driving malfunction but after a while driving in city due to a lot of stops, it pops up usually in 2-3 gear driving manual (automatic transmission). On the highway always 5 gear once I downshift. It’s really like a off and on thing.

CarlyMechanic

@Butter

Sparks and coils were replaced at the same time. Checked the spark plugs and they looked to be operating just like the others I checked. Its weird, when I start the car there’s no driving malfunction but after a while driving in city due to a lot of stops, it pops up usually in 2-3 gear driving manual (automatic transmission). On the highway always 5 gear once I downshift. It’s really like a off and on thing.

Inspect the wiring and connectors for cylinder 4's injector and ignition coil to ensure there are no loose connections or damaged wires. Electrical issues can cause intermittent misfires. If the problem persists, it might be worth checking for vacuum leaks or performing a compression test. Keep me updated on your findings or if you have more questions.

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