Very very rough idle and accel

[CTDiesel at aol.com]

The other day i unfortunately ran out of gas even though the guage showed 
above the red line....regardless from that point on after i filled up i have had 
a very rough idle, similar to a cylinder cutting out but once i reach about 
3000rpm i can feel something kick in and it runs fine at high rpm....i then 
replaced all the ignition components (cap, rotor, plugs, leads, coil and control 
unit) thinking that might be the problem as well but still that same thing is 
occuring....when at idle and sitting in the car you can hear the fuel pump 
humming normally but then every 15 sec or so you hear a sound like air is getting 
in the fuel pump ( similar sound to when you are running out of gas).  What 
should i do at this point?  A new pump and check valve?  or is it further down 
the line?

TIA,
DJ