My father bought a new L300 wagon with the V6 a few months ago. Nice car but the only thing I find obnoxious about it is the engine rumble when idling. Changing to neutral doesn't affect it. Turning off the ac doesn't change it either. It is a very loud low pitch hum thru out the car at idle. It is something that I would expect of a 4 cylinder engine, not a 6 and even with a 4, usually switching the automatic to neutral will change the idle speed slightly and eliminate it. Was wondering if this is a normal sound with the car or should I have my father get it checked. Fortunately for him he has lousy hearing even with 2 hearing aids turned all the way up.