Here'* the deal. My friend has a 93 Regal GS with the L27, and it is acting odd. He has a "clinking" noise coming out from under the hood on the passenger side. We pulled the belt off and the sound is still present. I took my mechanics stethoscope out and found the noise to be the loudest near/behind the water pump. Is this a bad timing chain or chain tensioner? BTW, I am assuming it is a timing chain problem by the miles, it has 288k on it. Anyone?

BTW if this helps, it runs shitty upon letting off the gas or revving slightly. It will pop and backfire through the exhaust/intake sometimes when he does that. No CEL.