How much noise should this make?
 

Two questions actually (and thanks in advance for the advice!)

1) When I am driving at moderate speeds with the top up and radio off, I can hear what sounds like a runnng faucet in my car. It is very faint and sounds like a running faucet one would hear through a wall. Am I correct to assume this level of noice is normal?

2) When I startup my car and put it into reverse, the engine (sometimes) seems to cause the car to gently vibrate a little. Freq. of the vibrations/sound pulses seem to be about 3-6 per second as I percieve it to be. Could this be from condensation build up or crappy quality gasoline?

Regards!