Two things. I haven't heard of a dose rate that high, normal mix is 640:1, or about 1 ounce per FIVE gallons of fuel. Second, did you add it and then nothing else between when it started running rough, or did you add fuel in the meantime? It sounds more like that, to me. I'd change your fuel filter and see if it's buggered up with anything, and for good measure use a can of Liqui-Moly Diesel Purge as directed on the can.
Considering the seeming thousands of people who have used TCW3 without problems, I doubt yours is 2-stroke related. Which TCW3 did you use?