I noticed this afternoon that my '02 Merc. 150 w/ 123 hours has begun making an ever so slight chirping sound at low (idle to approx. 2000) RPM. The noise goes away when I power up.<br /><br />The motor is running very well and I have noticed no change in performance at all.<br /><br />I began feeding it Pennzoil 100$ synthetic TCW-3 this year. I wonder if that has anything to do with it....<br /><br />Do you guys have any suggestions???<br /><br />Thanks.<br /><br />Brian