I noticed my Power MIG 255 was welding a little "choppy" the other day, and thought that I had the hose kinked or in too tight of a bend. Well, I straightened it out as much as possible, and it helped a bit (but not completely). So, I opened the door and actually watched the spool as I depressed the trigger, and could tell that the wire was not rolling off smoothly (jerky is the best adjective I can think of). Tension is OK, and there doesn't seem to any problems with the spool of wire itself. Is this almost certainly a liner problem, or are there other considerations I should make?