My 04 f350 has been running great since full egr delete new heads, studs, oil cooler ect since Feb. 2 days ago it started surging at all speeds. Plugged in my obd tool and no codes. I have lost some power and mileage. More black exhaust than usual. Also turbo seems to slow down much faster than before when I shut it off.

 

ICP sensor.

 

ep sensor, plug scanner in and go to data and check it, mine was saying 16psi when the truck wasn't running, also had underboost codes