need opinions... I have a noise on the left side of engine that I can here going down the road and it sounds like valve tap. It is the louds around 2900rpm and at cruise. If you accel, decel or go up/down a incline the nosie goes away. I have adjust the valves, changing perload, changed the oil to differrent weights and nosie doesn't change and has gotten worst over the last 7 months. Any help please.