Cable/liner problems can be the cause of some hard to detect/solve problems when welding.
All good advice but may I add to this, alot of this at home is caused by when the welder is stored the copper coating on the wire is not enough to stop oxidising, this rust if allowed to form gets trapped in the liner next time you weld, causing the wire to hang up,
so I suggest if you lay your mig up for weeks or months at a time to remove the roll from the feeder and store it air tight (tupperware etc) till next time.
I even wrap it in an oily rag (altho don't let this contaminate the wire), nothing like needing an emergency weld to find maintenance problems holding you back...
