Have a late 2000 2500..new body style with the 6.0 liter motor. Truck starts fine...when you go to take off and motor gets to 2000 rpm it sputters..if I ease into the throttle and feather it I can get it up to speed...however if I get agressive with the throttle its spits and sputters, it pings and generally doesnt sound good. Once I drive it for 10-15 miles and its fully warmed up.... it runs perfect and problem goes away....Shop replaced the O2 sensors and it may have gotten a little better but problem is still there. Would anybody have an idea on what it might be? Before I took it in I was thinking a bad plug or wire?? Im open for suggestions. Thanks.

 

Check the fuel pressure. Make sure it is correct and that is increases when the vac line is removed from the regulator

 

If it was a bad plug, wire, coil, etc, it usually wouldn't go away once the car's warmed up. May be a faulty Intake Air Temp sensor or Exhaust Gas Recirculation Temp sensor. I heard of a similiar problem with a GMC Jimmy, one of the sensors that detected the engine temp was fault so it had a hard time firing up, but once it warmed up ran fine. may be worth looking into more.