I scaned my car and got the code p0304. But ,I had the plugs ,wires and fuel sys

What is your question?

fuel system cleaned. But every time I top off my fuel tank and go over the line and drive a short distance the engine starts running rough and the CEL starts flashing I shut off the engine and the light comes back on for a fewseconds and goes out as normal. In between fillups the Car seems to run fine. The CEL does it normal off and on.