2000 Gt Engine Noise!

Sounds a little "light" to be a rod bearing. Perhaps a timing chain tensioner problem?

Either way, you're going into the engine.

Happened to me before. Take out your spark plugs and make sure they're seated and threaded properly. It might be a compression leak.

+1 on above. Spark plug blow out is a REAL problem on the 4.6's. In many cases the spark plugs blow out from being under or over torqued. Check all spark plugs and torque to the factory recommended torque.

OBTW, it's a lot easier to catch a loose spark plug before it actually blows out. Real PIA to perform thread repair.

Do you want an easy test to determine if there's a likely timing chain problem? Get yourself an oil filter cutter. Drain the oil into a CLEAN pan. Use the oil filter cutter to cut the top off of the oil filter.

IF there's a problem with the timing chains it will show up as metal debris in the oil filter from the timing chain rubbing the inside of the front timing cover.

After my experience replacing a failed motor from worn timing chains I always inspect the oil filter as part of regular oil changes. This alerted us to a problem in my Son's F150 before there was any serious damage done. Saved the motor.

Probably just me, but I would take off the valve cover for an inspection, I have been known to do some knucklehead stuff though.