New member with a new Stampede. New to the electric scene. I have a new Stampede VXL 4-wd. Ran 3 packs so far and here is my problem. Will not pull a wheelie-power seems ok but soft,speed seems to be good,but also has studdering when throttle applied (was told by someone it is called cogging). My son has a new 2-wd VXL Stampede and he can pull the front tires off the ground until pack runs down. I can run the same top speed-just don't seem to have the power on bottom end that he does. All new.all stock.even swited battery packs to make sure it wasn't the battery. Is this normal? Right now I am dissappointed withe the 4-wd. I thought the VXL's were not suppose to "cog" and had good power. What do you guys say? Again I am new to the scene-so may I have over looked something.So what do you guys think?