1990 V8 transmission differential vibration

[WHITEPATCH@aol.com]

Could somebody help a fellow enthusiast like myself who owns a 1990 V8 in
fixing my car.  I'd like to get a copy of the manual for the 1990 V8.  

There's this noise/vibration near the driver's footwell, that comes randomly
(at various speeds and rpm, most times around 20 mph @ 2k rpm), when i
accelerate.  If i let go off the gas pedal, it disappears, when i gas up again
at times it comes back, other times it doesn't.  I don't think its the
transmission and i'm pretty sure something's vibrating against the bottom of
the car that's causing it.  Also, when it happens, the car surges a little and
there's this faint whining sound. Your help would be appreciated.