Diagnose help - HPFP or intake needs walnut blasting

[patton001]

I am relatively new here so hi everyone.

I acquired a 2009 335i with about 40K miles on it about 4 months ago. Having a lot of fun with the car but I have an occasional stumble under hard acceleration and I have seen members here equate that with both the HPVP issue and the intake manifold needs cleaning with a walnut blasting issue. I have no codes so I am sort of shooting in the dark. Is there a way to diagnostically differentiate between the two known issues? I hate to just start throwing money at the problem hoping something will work.

Thanks for any input.

[jclausen]

when were the spark plugs replaced

[White94RX]

N54 or N55? Can't remember what is in a 2009.

[patton001]

White94RX N54

Gclausen - Plugs have about 4,000 miles on them.

[White94RX]

I would say you might need new ignition coils. Have any of them been replaced? The N54 uses the Bosch coils which are failure prone.

[patton001]

Hmmm...I will have to pull them an test. It has been my experience that coils are go/no go so my issue wouldn't be so intermittent if it was a coil. What do you think?

[White94RX]

I've had plenty that are on the way out and give a stuttering feeling when under a load, but not a dead skip and no check engine light. I'm sure your car would benefit from a walnut blast, but 40k is a little early.

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