When using my mig welder it seems to let the wire out ok until I start to weld. But when I start to weld it starts to pop all over the place and pushes the tip up and down and burns holes all in the metal I have the wire speed and amps set right but it still will not weld right. Can someone please tell me how I can get it to let wire out smoothly when welding. I have even tried to replace the liner in the hose and I am using the right polarity.