I like my PKS. It lights easily and, until recently, has preformed well with no problems. Now the flame has a tendency to surge; that is, the flame will burn evenly for a few seconds, become smaller, like the burner feed valve is being closed, then surge to a flame height above the original setting, as if the feed valve was suddenly opened. This oscillation
continues during the entire cooking
time. It isn't just one burner; all three burners act the same way, even oscillating in unison when more than one burner is being used. Cleaning
/ changing the nozzles has had no affect. I have checked the fuel
feed without flame and there is no apparent restriction. Also, I have tried varying the pressure on the fuel tank
, and there is no affect on the surging. What else can I check?