The same thing just happened to me, I googled it and found this forum. Lots of black oil spots coming out of walking foot. Yes, I had oiled it a while back (online recommendation if it was making noise), but had used it on a couple of quilts since then. This time of course the fabric was white !!! I didn't know where it was coming from until I removed the foot and found a black greasy spot on the plate. Used a facial tissue to wipe and get inside the foot, wow a LOT of black oil. Don't know why this happened, I had used regular sewing machine oil, so maybe it reacted to a black plastic or rubber part? My husband took it to his shop and cleaned it very well, but I ordered a new one, not taking any chances, and NOT oiling this one
