I have a Millermatic 180 that when welding thin material, after about 5 seconds, the welder will almost stop feeding wire, then catch up. When welding thicker material (greater than 3/16"), after about 5 seconds, the welder will completely stop feeding wire. I have to release the trigger and then pull the trigger again, then 5 seconds later the same thing happens. It does this the whole time I am welding, so I know it is not an issue with it getting too hot and shutting down. Any help would be greatly appreciated.