Bad check valve in well? (For Gary Slusser)

I just had the pump and the down pipe replaced in my well in April 2003. Everything was replaced -- wire, torque arrestor etc...
I just replaced the water pressure tank a few months ago and also replaced the tee, pressure switch, guage, and relief valve.
This is my problem -- I have developed a pressure surge when the pump kicks in. My system is set to 30/50 and when the pressure drops to about 28 or so the pump turns on and the pressure drops to 0 for a second and jumps back up to 30. After the pressure reaches 50 the pump turns off and the pressure slowly drops to 45 and stays there. The tank has 28 lbs of air in it -- should this be checked without water in the tank -- does that make a difference?
I have turned off the pump and drained the tank and refilled it but I still have the same results. I'm thinking it is the check valve in the well.
Also, how much of this should the plumber cover if the pump needs to be pulled? As I said, it was just replaced in April of 2003.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.