So bought this 01 thinking it was going to be an easy cracked exhaust manifold fix... The thing was broke in half onthe passenger side. Well it was hiding a knocking sound as well... Start the car up cold, I get a knocking at 2200ish rpms, at idle nothing. Rev it past 2k-2200 it does get louder. Once it's warmed up it's more noticeable at idle the kkocking. The dip stick tub was broken and found out I have a yellow round handle stick... Quiet frankly my 99 cougar has the same dip stick, I know mustangs have the black T handle dip stick.... Sure enough get one from the wrecking yard and the readings are totally off, "cougar" stick reads 1/2inch lower reading meaning "full" is really low area. So who knows how long the previous owner was running this stick and not sure full 5.5qt of oil in her. So I started to tear it down pulling the valve covers, passenger side is freaking shiny and brand new looking... The driver side looks as it's been ran with oil and carbon everywhere, everything looks normal with no loose rockers. Not sure if this could be my problem hopefully in the heads and not a rob bearing or main bearings. Any thoughts?