[ExTREME]

When I'm driving at low speeds it seems to studder, and/or bog down. Then when I get on the gas a bit it seems to bog then go up. Also, when I'm idling if I rev it up a little bit it seems to bog then go up and then when I let off the throttle it drops way down and almost dies. I don't sit there and wrap the piss out of it to sound cool, I just did it to test it out and it does almost die and it seems to pause. Is this a spark problem? Fuel pressure? Vaccum leak?
Thanks
-SA