Clearing codes

I have a 2007 International with the cummins isx 870. I had it serviced, all filters and oil changed. the next day it started blowing black smoke and started losing power. My truck is wide open " meaning itll go 120 mph ". when im in 10th gear running 70 to 75 mph its runs like a champ, but when i hit a hill it starts dumping black smoke like crazy. empty or loaded, even bobtail, and im forced to down shift, but it seems i downshifted to soon. I smash on the peddle and nothing happens, eventually it will gain its power back and roll fine. truck blows smoke when changing all gears, and when in say, 4th gear, it pumps smoke and lags when i hit the peddle. Ive checked everything i know to check, egr cooler is recently new, ive tried unplugging the EGR Valve, it still does it. Matter of fact, ive unplugged everything for the most part and it still does it. i put a launch scanner on it and it diagnoses as bad cam sensor, and bad turbo actuator were the only faults to appear. i replaced both parts brand new. and it still does it. If i dont clean out the old codes after repairs, will the truck still malfunction until i do so? somebody told me i had to clear the codes after repairs to fix the problem. if so, i need to go buy another scanner. If that dont work, i guess i should buy a new turbo and new EGR valve and change all sensors? i do everything i can do myself, as labor is ridiculous high, but then again, so is chasing ghost problems.