Rough acceleration on Venture

I have 2000 Chevrolet Venture that is running rough intermittently, it seems to sputter when the gas is pressed to accelerate. If the gas is pressed down long enough, the Van seems to backfire and does not accelerate

While in idle there are no affects of this, seems to idle fine, only when the gas is pressed, happens even in park while pressing the gas.

This problem became apparent when the weather was wet (while raining) figured it was electrical (wiring or plugs), now it seems do to it most of the time regardless of the weather.

Looking to fix myself, if does not involve ripping engine apart.

Any help would be appreciated.
thanks,

When did you last replace the fuel filter? I suggest this because the engine idles fine, but runs rough when it needs more fuel.