Abbrandt27

Hi, I basically don't know anything about power tools, so I need some help. I just got a jigsaw, the dewalt dcs331, and I'm having a tracking problem. I know jigsaw's aren't meant for cutting perfectly straight lines, but regardless, for almost every blade I have (a set of 6), each one has a tendency to pop up and to the left off the tracker. The tracker is on the back of the blade, and is simply a wheel with a groove. Even when I have a straight edge lined up with the foot of the saw, the blade still ends up veering left, and bending, making a slightly slanted line. Is there a way to adjust this? Reviews say that this is a very nice saw. Is this something that just happens with all jigsaws? One possible problem could be saw dust. It has gotten quite dusty, so I'll clean it out soon an see if that makes a difference. Any replies are greatly appreciated. This is the saw: http://www.dewalt.com/tools/cordless-saws-jig-saws-dcs331b.aspx