GM-GMC: takes around 10 cranks to start s-10 p/u, fuel pumps, check valve

Question
I have changed everything that I could think of to fix this problem.  I have a 1987 S-10 and it takes me about 10 turnovers to get it to even start and it then is running rough.  Any suggestions would be helpful.

Answer
There is a check valve built into most fuel pumps which is designed to prevent the fuel on the feed side from draining back into the tank.  What happens when this check valve malfunctions is, the fuel pump must re-prime the entire fuel system inorder to build sufficient pressure to start the vehicle.  Another way to check this is to turn the key to the on position.  Wait a 10 seconds or so.  Turn the key off.  Wait 10 seconds or so.  Turn the key back to on, wait a second or two then try to crank it over.  If the truck start easier, then you are likely chasing a fuel problem.
Hope this helps