Air in my fuel system?

[cnhunt]

2002 Excursion 7.3 powerstroke 240,700 miles. I repaired leaking hpop o-rings and rebuilt the fuel bowl. Everything seems fine until recently i noticed the following; loss of power, poor mileage. I try to accelerate onto the highway with the pedal on the floor and no noticeable pick up in power.

I was at the drive in movies and noticed that with my key in the on position the "hum" of the fuel pump never stopped. The movie was 2 1/2 hours long. I heard it when i turned on the key for the radio at the start of the movie and still heard it when i got out after the movie. Shouldn't it shut off at some point?

Also noticed a long cranking time during start up.