Is this a common issue? It sounds like an internal bearing but I'm not sure.
The car also has a bad exhaust rattle at times but I'm not sure about the rpm ranges they occur at. I can't determine if this is related to the first issue. It seems the car has a rear flex pipe and this flex pipe is completely rusted up and not flexible. I'm going to have that replaced and see if it affects the rattles

My wife just got the car from her grandmother and I'm afraid it is damaged or is going to fail soon. I may take an oil sample at 1500 miles and send it out for analysis.

Are Main or Rod bearings common to go out on this engine?

The car has 164K miles.

 

No, the main and rod bearings don't usually go out on these F22 engines. They're pretty solid.

Try listening if the knocking/rattling noises go half the speed or constant with the engine RPM. Half the speed would be the head/valvetrain noise; othewise, constant would be the bottomend.

 

maybe, could be timing belt should be replaced at 105k. do u know if it was???? just did one to a 98 accord w similar symptoms ur sayin and noise all went away

 

just an idea