2006 ISX CM870 High Pyro, surging under load

[tree98]

The ecm doesn't know your getting high egt's, there is no sensor for it. The black fuel is probably asphaltane, pretty common occurrence. As Rawze mentioned, did you put regulated air to the turbo actuator to verify smooth and full range operation? Also could be the turbo controller as Rawze mentioned. Replace it with a genuine cummins NOT an aftermarket of any kind. These controllers can give you problems and never throw a code