Cm871 codes 2961 2764 4214

[JetHauling]

Hi guys, I recently purchased PETE 388 with a 500 in it. I'm having problems where the truck will limit the turbo to 20psi. Before the turbo limits and the truck is running proper the check engine light will flash for a few seconds and go away, with the occasional quick and short turbo "burp"After the turbo derates they won't come on again.. Using the Cummins software I was able to pull this codes. Sometimes it will do this for an hour, sometimes for the entire day and carry over until the next morning.. I've replaced the sensor on the intake because it was all blocked up with soot.my outside air temp gauge is traded way below what it should be, I'll be changing that this weekend as well.
thanks for your help