One problem related to service engine light on has been reported for the 2013 Ford Focus. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2013 Ford Focus based on all problems reported for the 2013 Focus.
At an intersection, the car sputters from a stop and sometimes stalls. Likewise, after re-fueling the tank the car stalls 2-3 times in a row on ignition before starting and staying on. When approaching a stop, the car has sometimes had the other dashboard warning lights come up and felt like it was about to stall, with the rpm gauge bouncing around near zero, but has not fully stalled during deceleration (possibly due to me pressing on the accelerator to prevent the stall). The service engine soon light came on shortly after this began. At that time, the fuel gauge also began to "stick," not moving from position until the car would be stopped and restarted, and mis-representing the number of miles left before needing to refuel. I'm currently at a Ford dealership to get inspected and repaired. I've been told that it has something to do with a pump, but nothing more at this point.