M20B25 Weedwhacker?

[CRH_E30]

Earlier this week, my engine started making some weird sounds between 1k and 2.5k rpm, sounds kind of like a weed whacker. Opened the hood up yesterday and revved it a little, sounds like its coming from around cylinders 4-6, but I can't tell what side of the engine it is coming from.

Anyone have any similar problems? Or ideas for me to try? I've already ordered intake and exhaust manifold gaskets and will be replacing those this weekend.

[EatsHondas]

Pull Seafoam through the vacuum line (that runs from the fuel pressure regulator to the intake manifold, the vacuum will suck it toward the regulator) to test for any exhaust leaks. The leaks will smoke white.