I know there are tons of threads on this and I have serached and searched but seems like so many of them are never solved. So i apologize for starting another one. But anyway, 2001 LB7, FPR is newer, less than 5,000 miles, injectors have about 3000 on them after all 8 were replaced. Did a head gasket less than 2000 miles ago. Starts fine when cold, surges very little at idle. When in gear, surges so bad that if you are not firmly on the brakes, if will push you. Once warm, no surge at all but cranks very long prior to starting. Just did a fuel filter head rebuild. Still surges the same way. When cold, primer will get hard after pumping, but will get soft after about 15 minutes. (same before the rebuild as after)Checked all the fuel lines, found no obvious leaks. Just out of ideas. Hoping it is not the CP3, but what else to check is beyond me. Could the injectors and/or FPR be bad already? Just looking for some help. Truck is driving me crazy trying to figure it out. (note that the surge has been present prior to all the new parts and is still there....so figure it has to be that very expensive CP3)????? Any help is appreciated.