I'm coming up with a code that is a multiple cylinder misfire.Cylinders 2,4 and 6.Sitting at idle in park everything is fine.When I bring the RPMs up to around 2000 the car starts spitting and sputtering. I changed 2 coil packs and spark plugs to no avail. I have a new fuel filter but have not replaced it yet.The car only has 50000 miles on it.Any help would be appreciated.

Thanks
Mike Bittner