Last week our daughter filled the car up with gas, tank was close to empty 2014 outback with 198000 miles. She drove home from the gas station with no issues, the next morning went to drive it and it would start fine idles fine with no misses but has no power when driving and surges especially when going up an incline. I immediately put a can of sea foam in the tank and that didn't help, a mechanic friend hooked his engine analyzer up and no codes everything looked good spark electrically. I'm thinking bad gas or the fuel pump is going? Our daughter says she didn't put diesel in it. The car does start kind of hard when cold and has done this for awhile. Not sure what to do try to drain the tank and put in some hi octane gas, or look at replacing the fuel pump?