Tension Control. All of the sudden the top of my fabric has loops.... When reading the

Question

All  of the sudden the top of my fabric has loops.... When reading the manual, it says that my upper tension is too tight.... but I have to take it all the way to Zero to get the loops out, but then of course it's not tight....it's more like a basting stitch. I've re-threaded my tob and bobbin thread.... I usually keep my upper tension between 3 and 4 and it's perfect.... but all of the sudden it isn't working. I just got my machine in May, so it shouldn't be acting up like this yet...