On my 2003 coupe, my oil pressure gauge was nearly as active as my speedometer. Ok, not really, but it moved ALOT. My dealer told me about this "feature" when I picked up the car and told me not too worry. Even with all the bouncing, I never noticed an issues related to an oil pressure problem, so I stopped even looking at it. I am not sure if my 2004 does this as well, so I will check this weekend.