My chevy silverado 1500 with 5.3L v8 has service engine light and p0300 (random eng misfire) and p0131 (o2 sensor- bank 1 sensor 1). The truck idles rough sometimes and at times the check engine light flashes while at an idle and idle gets even rougher. I have changed the plugs and wires, ran seafoam through the brake booster vac line, and still nothing is helping. The truck also has an extremely strong exhaust smell. Any help is greatly appreciated!