2005 hpdi

[tully]

since the new power head on my motor it was running very good then they said the throttle postition needed to be set different from 6.4 to 6.3 now the motor is a great of the hole good and good at top end they checked it on the computer and it shows nothing wrong the motor sounds if it is not opening up not a smooth sound at 3500 where i usually run the engine i have changed plugs but no good also running ring free any suggestions

[tully]

the engine fills like it is skipping at all rpms when it has settled out plane they also put a water fuel seperator on it not really running bad one of those things that drives you crazy