No power
 

Hey guys I'm having a pretty aggravating problem with my 2000 GMC k2500 it has a 5.7 vortec and when it idles it thumps like a cylinder miss and when I take off it acts like it's not getting enough fuel I've replaced all the ignition and the fuel pump and fuel filter only thing I haven't replaced is the fuel pressure regulator but it's fine when hooked to a gauge idk what else it could be could someone help me out with this?