engine stumbles when accelerating

Hey I have a problem, whenever i accelerate especially around 4400 rpms(vtec engagement point for intake) my engine stumbles. I replaced plugs around 3 months ago, I replaced plug wires around 2 days before this started happening, and i just changed fuel filter yesterday(so it's not that). Oh yeah and my plugs are cloudy white at the tip. Some help would be appreciated. Thanks:)