Never used to be like that. Any idea what has gotten weak or worn out that would cause it?

I've had it too long. Definitely got my money's worth. Worked for 4 years. Just wondering if there was a resistor or something going bad on the circuit board that affects the feed motor during actual welding that is causing the jerking. Feeds smoothly if your not welding.

I have a MIG welder that is acting up. It is a cheap, Harbor freight welder. I know, you get what you pay for. It used to work good. I have my Lincoln arc to fall back on but this one is portable and I'm not wired for 220v everywhere one my property. The MIG welder feeds perfect unless you're weldin...