try to determine if your problem is fuel,spark,are compression first.one thing i see alot is when most people rebuild engines they neglect the fuel system "I E" the fuel pump diapraghm,vst tank and it's filters,and last but not least i would not rebuild one w/out pulling the injectors and having them cleaned and flow tested,the life of your motor " fuel/oil mixture" is flowing through them " take care of them". look at your plugs first and take a color reading try to see if one is oddball compared to the others.