I have a 2001 f250 7.3 with 260k it starts good and runs smoothly but lacks power big time. It all started after i fueled up one day and was very hard on fuel almost burnt double then normal. I topped up tank when it was down to a quarter thinking it was bad fuel but still acks the same. Im hoping that once i burn this new tank of fuel it will smarten up. Just wondering if any one else has had same problem or maybe something else is wrong. Thanks

 

Any codes ?

 

Checked codes and nothing showing

 

Have you drained the fuel filter/ water separtor ?
Try a new filter too .