might be a simple fix but try your spark plugs..might be new but gaping might be off or they might be the wrong kind...the so called uprated plugs usually hinder running or performance...genaral rule air fuel spark..if youve checkd air n fuel then the sparks the problem..
check fuel pressure should be 40-45psi
check air unplug maf...youll know if thats the problem
check spark unplug spark plug n turn the cas,,spark plugs will spark but somestime itll spark but n heres the killer youll have the "uprated" sparkplugs n thats the problem
get the ngk specifik to the engine
hope that helps