93 S10 Blazer fuel issue
 

We have been working on my son's 93 Blazer for 2 weeks now and are now at loss of what else to do. Great running engine and starts up fine. Sometimes you can drive it for about 10 miles and then it dies but will start up again. We replaced the fuel pump (for the 2nd time because the first time Advance gave him one for a s10 and not the s10 blazer). We replaced the fuel filter, the fuel pump relay the fuel control. Put in new plugs and wires. Now you can barely get up the road and it hesistates and dies. Plus it used to blow out a blueish smoke at start up. Now it is contiuously blowing smoke while idling. Have we missed something? Any other ideas would be so appreciated.