2001 Xtreme P0701 P0704 codes.......

Hello All, First off id like to say Thank You for the help!!!
Ok, I have a 2001 chevy xtreme blazer 4.3. I recently purchased the vehicle about 3 months ago and was hard starting... Would crank over longer than usual to start and was told it needed a crankshaft positioning sensor. I replaced that sensor and it still seemed hard starting so I did some research and came to the conclusion it was a bad fuel pressure regulator. After watching various videos on replacing the fuel pressure regulator i went ahead and replaced that as well. Now, Truck starts fine! But!! i have 2 codes P0701 and P0704 popping up.... I have checked all vacuum lines and hoses.... Twice!! Sprayed carb cleaner around the intake with No change of RPM's.... Replaced the EGR hose, even used silicone on the upper intake to prevent any vacuum leaks. Only thing I seem to come up with is that I have a bad/clogged injector or my fuel pressure regulator I replaced is bad....??? Any help will be Greatly Appreciated!!

I have finally cleared my codes and truck runs great and passed the emissions test!! Only thing I replaced was the Fuel Injection Spider. And I purchased the upgraded MFI system! Got it on Amazon for $230.00 free shipping and same day delivery! So if anyone is having the 701-704 codes and are coming up empty, Change the spider! http://staticaf.com/vbulletin/images/smilies/smokin.gif