newbie question about engine surging and poor mileage

Hey all, Im new to this forum. I have a 1995 villager, which idles beautifully and has good high end power. However, when accelerating hard in the lower RPMs i experience a lack of power, accompanied by surges of full power. The problem is worst in 2nd gear, and seems to be worse when it rains, but im not sure if thats just my imagination or not. When you put your foot down the engine doesnt give much power and then every second or two (rythmically) i get a little surge of power for a fraction of a second. This is accompanied by crappy gas mileage. The problem seems to have come out of nowhere, but I cant recall when. Im a very slow driver to save gas. When I bought the car a few months ago obviously i dropped the pedal to the floor, and there was lots of smooth power. My intuition is telling me that the problem is not fuel system related, because it just sounds like plenty of gas is being dumped in to the engine, the engine just isnt using it somehow. Meaning, when the surges of power come on the exhaust noise doesnt change much, indicating to me that plenty of gas is being dumped in to the engine. does not feel transmission related. The description may make it sound electrical (it may be, im no expert) but it doesnt "feel" electrical because it happens smoothly and consistently. The problem isnt especially rough or violent, just annoying, and I cant get around town very fast without flooring it. If you have anything you can suggest to help me I would REALLY REALLY appreciate it. Im going to post on some nissan maxima forums as well. thanks!
-Grant

i would start by checking the distributor cap / rotor and wire. Check plugs while your at it. i believe spark plugs get changed every 30K miles on the 95. they are non platinum plugs. If plat plugs are installed. remove and put proper plugs in. Plat plugs run to cool. I would start by checking that first. GL..