I'm curious what my engine is "supposed" to sound like. When I am driving around town, taking it easy on the throttle without the radio on, I can hear two distinct sounds from the engine compartment. I hear the low, throaty sound of the engine and I hear a clicking sound. The clicking speeds up and slows down with RPM and even goes away sometimes (not just when I let off the gas). The interior is very quiet so both sounds get muted a bit but the clicking sound stands out and drives me batty. What do you guys hear when you are driving?