Alright hoping to get some feedback here. I bought my truck bone stock and kept it that way till a few weeks ago when towing my 20' race trailer the DPF started giving me issues @ 148K miles. The next week I installed the 4" exhaust and the EFI by millken diesel. i got the blocker plates for the EGR but have yet to install because after doing some research i want to do the Y-bridge upgrade with the LB7 up-pipe to completely remove the EGR. I was towing today and it was doing great ( I keep it on the stock tune with deletes while towing) but about 15 miles into the trip I noticed a loss of boost and it would seemed like the turbo vane position would cycle about every 5 seconds and would blow a small cloud of black smoke and then lose power to the point of it going into limp mode and throwing the p0299 under-boost code. i got off at the next exit of course and limped it the 45 min to the track and cleared the code and it ran phenomenal all the way home. I'm looking for anything help in beginning to troubleshoot. Could not blocking the EGR cause this? Thanks in advance for any help here cause I'm stumped.