P0251 code. Upcoming problem?

[drasko]

Ok i towed about 8k on friday with the quad box on 3 250 miles and back 250 with an empty 35 ft gooseneck. Friday night while coming up a big hill with no trailer and moderate pedal, my engine light came on. I checked codes and saw the normal 0148 fuel delivery error and 0236 boost rationality error but then i got the 0251 injection pump fuel value feedback code. I cant tell if there is a loss of power or not but its seems a tad bit quieter, but i did tow all day so i think thats just my ears being used to 6 hours of the loud drone. Is this the signs of a bad pump or maybe a popped relief value? Any help is appreciated. Im gonna run with no box for the week to see if it goes away.