Truck Repair: ISX 500 ST engine performance, cummins engines, isx

Question
2005 Int'l 9900 was purchased in June 2004. It currently has 80,000 miles. The engine has a flutter and reduced power. No codes, they have changed 2 injectors, 3 ERG valves, they have checked the 2 little EGR lines on the left side of the engine, they have done everything they can think to do but can not find the original power.
Any input you may have would be greatly appreciated. I have fought this problem for the last 7 months and am getting very frustrated.

Thanks!
Mark

Answer
Are you taking it to a Dealer or Distributor?I have changed several injectors because of the "flutter" when you accelerate hard.If you have a hard to die problem,that is a injector problem too. I said Distributor because thats all they work on is Cummins engines.If you are not sure where a distributor is,call 1 800 DIESELS.