Och

iTrader: (3)

Check the fuel pump once you're at it.

lp_yang

changed the coils..no difference...can it be the egr???,,,i bought the new MAF from autozone for 250

Chilkoot

can you be a little more specific on your problem please? what RPMs it happens, where in the engine bay you hear the noise from, where in the throttle the problem arises and whether it comes and goes at certain RPMs or gets worse linearly?

are you getting a CEL, or any other dash lights? When you have the key to accessory before you turn the car on do all of your dash warning lights illuminate? one could be burnt out and covering up a problem. if it's as bad as it sounds there should be a code of some sort.

my blind guess would be o2 sensors and burnt out CEL bulb, making your engine hunt for an a/f mixture, but the more information we have the more we can help.