Rough running, feels like its misfiring

Hey All, im hoping someone can shed some light on a problem im having with my all stock 04' 4.0.
So, all of a sudden my truck runs like crap. I'm in NYC and its been really cold and I just don't drive the truck but a few times a month, with the exception of moving it from side to side for the "street cleaning". Yesterday, I went to take it for a drive as soon as I started it the motor was running rough and it seemed like the exhaust note was louder and the truck was shaking...I popped the hood and the motor was kind of bouncing around and the idle was erratic. I was thinking maybe its just really cold and once it warms up it'll get better.. it seemed to smooth out a little. HOWEVER, when giving it more than 1/4 throttle its sputters like its running on fowled plugs, and has no power(relatively speaking for a slow-*** truck). When I returned back to the city and parked the car i popped the hood again and the motor is still bouncing around. I was just staring at all the little hoses and sensors and decided to pull the vacuum hose off the top of EGR valve and then the motor and idle instantly smoothed out. I haven't driven it yet to confirm its fixed but was wondering the mechanics of what i did and what happened. Thanks