Chevrolet: Extreme knocking in my malibus engine, rod bearing, exhaust manifold

Question
Yes it vary's from rpm level it is louder under 2,000 rpm and any higher it is not as loud but it gets faster.
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Followup To

Question -
Well just the other day, I drove up to a drive through and thought I heard a noise so I put the e brake on and popped it into neutral, then revved the engine and noticed a fairly loud knocking. I knew it wasn't my octane because I know what that sounds like. I figured it was a rod bearing. I'm about 1,000 over due running on synthetic so maybe I have bad oil flow. I figured I'd ask an expert before I do anything expensive. Thank a lot, Tyler.

Answer -
Check your oil level. You might be low on oil or have an oil leak.

Does the knocking sound change with the rpm? Aka get faster with the rpm?

Could also be an exhaust leak at the exhaust manifold.

Answer
Ok well that helps. I take it the oil level is fine.

The reason its quieter above 2000 rpm is because your engine gets louder and the oil psi goes up.

Sounds to me like its either an exhaust manifold leak (need new exhaust manifold gasket $15) or something in the valvetrain is loose or broken.

Take a long screwdriver and touch it to the valvecover. Put the other side to your ear and listen for the tapping.

Move the screwdriver to the exhaust manifold and see if you can pinpoint where the tapping is coming from.