Hey, Lewis.. welcome to the CEG..
First off, I would start with the most obvious of things:
When the car begins to give bucking/jerking or rough rides on acceleration when below a 1/4 tank of gas, this is primarily an indication of the lower fuel pump sock becoming clogged and not allowing enough fuel flow to the engine.
When above 1/4 tank, there is an upper sock that is still clear to allow fuel. Replacement of the entire pump is not required, and simply the sock can either be removed, or replaced (there is still an internal screen, as well as the fact that the design has changed and aquiring a lower sock in the same design as yours may prove to be fruitless)
As far as the "noise" you are saying exists... what type of noise? (describe it in ANY form or fashion your can equate it to..) When does it happen? Where does it come from? What are you doing when it happens? (accelerating, braking, coasting, truning, revving the engine?)
Is the noise dependant on ENGINE speed (ie, the faster the engine turns the faster, or louder the noise is) or vehicle speed (ie if you are doing 60 it will always sound the same, even if you were to put the car in neutral while doing 60, the sound doesn't go away)?
You mention a 2000, but providing the engine size, model (SVT, SE, LX, GL) and miles on the car will also help provide some relief for your troubles...
Let's see what we can do for you..
Ray
