Hi,
I own a 1999 Mercury Villager Estate van.  Recently I started hearing
noises under the front end of the van.  The first noise occured when I
would press on the gas after coming to a stop.  It sounded like 2 or
three bumps....I'm not really sure how to describe it, it is not a
sound like metal hitting metal, more like the sound a vehicle makes
while going over a bump, but not as severe.  This does not happen
every time I press on the gas after coming to a stop, but probably 60%
of the time.
The second noise occurs less often, but after the 'bumping' I have
been hearing a grinding noise.  This also stops once I have pressed
fully on the gas pedal and have accellerated.
I have not had any trouble starting the van, and I do 'feel' the noise
under the front end of the van as they occur, just like a slight
vibration under my feet.

Does anyone have any idea what can be causing this?

Thanks,
Shannon