Engine noise

If it is detonation (sounds like somebody shaking a tin can full of marbles), start by looking for missing/disconnected/defective knock sensor. Several other possibilities exist but that's where I'd begin.

Regards, Al.

Possibly a loose or broken exhaust pipe or exhaust manifold.

Could be a cracked flex plate, just a guess. A car will run fine with a failed flex plate, my Chevelle had all four ribs broken, yet the car ran fine, occasional noise when making sharp turn.

I took it in for spring replacement, and the mechanic told me after a test drive, that he wanted to remove the flywheel cover, and look at the flex plate, when he showed me chips in the pan, I told him to go ahead and change plate. I was suprized when he showed me the old one, and was dumbfounded to realize car ran at all.