My miller 135 mig machine has started acting up and I'm not sure what this is all about. Sometimes the weld is full of holes and once I stop pulling the trigger the weld puddle will grow a snake deal like the old fireworks for kids, it's behaving like there's no gas. The nozzle is dirty I've tried to clean it up but it seems like maybe a new nozzle is in order. What cause this type of malfunction?  Any answers would be helpful. Liner? Wire corrosion? Nozzle? Gas issue? See the large hole inside? Now I have to cut that out and get the weld in there correctly. But this is frustrating. Thank you welderskills JODY COLLIER