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2020 330i Misfire and Check Engine Light After Cold Start

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Ashley M. · rep 0 · May 22, 4:04 AM · 1 replies · solved · Question

My 2020 BMW 330i (G20) has been acting up lately. A few mornings ago, after a cold start, the engine started running really rough, almost like it was shaking. The Check Engine Light came on immediately and started flashing for a bit before staying solid.

It feels like a misfire, especially at idle. When I try to accelerate, it feels sluggish and not as smooth as usual. I've tried restarting the car, but the CEL stays on.

I hooked up a basic OBD-II scanner, and it pulled a P0301 code, indicating a misfire on cylinder 1. What could be causing this on a relatively new car? Is it something I can check myself, or should I head straight to the dealer?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:04 AM

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ClearTheCode guidance (Bmw · Diagnostics & codes)

Summary: For 2020 330i Misfire and Check Engine Light After Cold Start, work through these steps on your 2016+ vehicle:

  1. Confirm the symptom — note when it happens (cold start, highway, after fuel fill, etc.).
  2. Scan codes — save all pending/stored DTCs; don't clear until you've recorded them.
  3. Check TSBs & recalls — look up your VIN for open campaigns and known fixes.
  4. Inspect the obvious — related fuses, connectors, fluid level, and recent repairs.
  5. Test the common fix — follow model-specific service procedures; one change at a time.
  6. Escalate if needed — burning smell, no brakes, overheating, or stalling in traffic → shop visit.

Owner reported: My 2020 BMW 330i (G20) has been acting up lately. A few mornings ago, after a cold start, the engine started running really rough, almost like it was shaking. The Check Engine Light came on immediately and started flashing for a bit before staying solid.

It feels like a misfire, especially at idle. When I try to accelerate, it feels sluggish and not as smooth as usual. I've tried restarting the c…

This is educational guidance, not a substitute for hands-on diagnosis.

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