My brother has an 02 Mitsubishi Diamante that he just picked up with 61,000 miles. Had the timing belt done about a month ago. They replaced the tensioner while they were in there, said it was no good. Also had spark plugs done. Now, when starting up cold, after warming up for a few minutes, it starts making noise like marbles rolling around in the engine. Valve clatter maybe? Dunno, but it's very noticable. It goes away after a few minutes, but does not come back until you start it up cold again. Other than that, its running great. I was thinking of giving it an Auto Rx treatment, see what that does. Any ideas?