Pelican Parts Forums - Why is my car failing the smog test?

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Question: I have a 2000 328I. I've had a misfire on Cylinder 5 a few times. Cylinder has been switched, spark plugs and coil changed out. A year later my "Check Engine" is back on. Light goes on and off occasionally on the dash. Was off but still failed smog. Car runs smooth though. Mechanic says I need a new Vanos. Will replacing this fix the issue and help my car pass smog?

Yesterday I noticed gas gage is reading incorrectly also don't know if that's connected Please advise.

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This post was auto-generated based upon a question asked on our tech article page here:

What are the codes now? You can go to most auto parts stores and get the codes pulled for you. Do you still have a misfire on cylinder 5? What do you mean when you say the "cylinder was switched"? How do you switch a cylinder? The gas gauge problem usually leads to EVAP codes and a bad VANOS you should notice with lower performance from your engine.

- Nick