Surging after K amp N install

[Ameration]

Added the K&N FIPK intake to my 2006 a few weeks back - now I’m noticing a surging around 1,800 RPM’s that wasn’t there before.

Thoughts as to why? This was the only change made.

[Steve M]

Can you put it back to stock and see if the problem persists?

Could be related, and then again, it might not be.