I seem to recall reading that synthetic oil (Mobil 1 in this instance) usage virtually eliminates camshaft lobe wear in a dual overhead camshaft engine, such as the Toyota 3.0 V-6. Therefore, the need for the valve lash adjustment is negated. I have 133,000 miles on the engine and it performs like it always did. No oil usage at 5K oil changes and 30 MPG at 75 on the open road (little traffic out here in the West). I've never adjusted the valves. The engine is super smooth running. Do I need to check the adjustment, or is it just a waste of time?