ISX450.......unrealistic expectations?

[Rawze]

egr tune-up.

pressurize entire engine and fix leaks.

inspection of exhaust and dsecomp tube for restrictions. - your symptoms of weak power and hard to get past a certtian power sounds exactly like intake or exhaust restrictions somewhere.
here is one good example - http://rawze.com/forums/showthread.php?t...07#pid1807

boost and pyro gauges A.S.A.P. -- every truck should have them.

remove, take pictures of DOC, DPF, and face of SCR. Have DOC and DPF baked, de-ashed, and flow tested.


Check ecm for any fuel related codes.

Inspect the fuel pump and REPLACE THE GUTS OF THE FUEL PUMP A.S.A.P. if it has more then 400k miles on the components. Those common rail ISX fuel pumps, when they start going bad will destroy the entire engine and the only symptom will usually be a bit of power loss or low fuel pressure codes.