I had the same issue, I recently had my fuel pump go out and had it replaced. Shortly after that i noticed that it still surged a little and my service engine soon light came on. I took it back to the repair shop and had them replace the fuel filter and check the code. When he pulled it up it said o2 sensor 1 bank 1. He reset the light as i told him i would replace it and now the light is back on after the next cold startup. Can the o2 sensor cause the little surging that i get and if so, is sensor 1 bank 1 located on the drivers side nearest to the engine. Any help would be greatly appreciated.