Pontiac Repair: Vibration on 2001 Grand Prix GT, front end vibration, pontiac grand prix

Question
I have a 2001 Pontiac Grand Prix GT with the 3.8L V6 engine, automatic transmission and 141K miles. I was having noise in the front and the ABS and low trac light was coming on.  Had drivers front hub bearing replaced 3000 miles ago and it illiminated the ABS and low trac light coming on while driving but still have front end vibration.  The vibration seems most prevelant when going over bumb and engine under power.  If I am just coasting I do not notice it. Low trac light does still come on once in a while when taking off from a dead stop but this has always been on dry pavement and no slipping of the tires.

Answer
Hi
As for the Low trac/abs lamp I would suspect the Wire harness is rubbing against the A/C Accumulator on the drivers side below the air cleaner box.
It is a VERY common problem on these vehicles.
( I say this IF the ABS system has been scanned for codes and none found)
As for the Vibration, is it noticable at any certian speeds? do you feel it in the steering wheel, or the seat, or the floor or all above?
Please follow post back.
Thanks and will wait on your post
Pawl