What are your thoughts

[Dumbtrucker12]

Ok so I am looking for advice I have a 2012 Pete 388 with a 2010 isx 15 motor with Def fluid and everyonce In awhile it will make a turbo cough when I shift. (Is this normal) I had it in the shop last week they replaced the turbo a nox sensor and the 2 plungers in the fuel pump. Still coughs every once in awhile with new turbo. They said that one plunger was stuck and cracked and it was only running off of one plunger they also said that if they would of not caught it it would of broke and bye bye motor now the problem I got out on the free way and man my truck was moving it had never ran that good since I have owned it. (Bought in oct15) I was hitting 40 pounds and it was running awesome well I stopped 100 miles down the road was at the back of my trailer and the engine dropped way down in idle like it was about to die then idled back up when I got in the truck it said hi exhaust temp I thought that was weird and took off well from that point on my truck has not ran like that first hundred miles it only hits about 32 to 34 pounds and then about 120 miles down the road the check engine light came on it said see opp manual well it stayed on till the next morning I delivered and when I went to go to the mechanics to have the light checked it went off well I still had them check it they said it was a nox sensor and that was last Tuesday and the check engine light has not come back on but the truck has not ran like that first 100 miles either please help I watched the video on egr tune up and plan on doing it when I get home I have already taken the crossover pipe off and cleaned it it wasn't that bad but still. Anyone know what's up with my truck Thanks in advance