using stargon 90% argon 8% carbon dioxide and 2% oxygen. its not all the time but i have trouble with the wire not reaching into the weld zone the way it should. it kinda seems foamy or maybe irratic not really sure how to explain it but it doesnt flow smoothly like it should also it has either black or white soot around the weld zone. i am in spray so the wire is running fast but not any faster than usual. feeder wheels are good new liner new tip nozzle and diffuser but it stills does it. using a miller 302 with a 24a feeder. i know its the gas because it will be running fine and they bring a new batch of gas and it starts back to running bad. the penetration is very poor and it has holes in the weld like the wind blew the gas but no wind what so ever. has anyone ever experienced anything like this. or can anyone tell me what exactley what happens if certain gases are not to the right % because this has been an ongoing thing for a long time and i really like the guy we get our gas from and dont want to change companies . thanks for any help