I'm having trouble figuring out the cause of a P2579 CEL reoccurring problem. The back story is I have fully deleted the truck with 4" exhaust, EGR/Cooler Delete, and EFI Live from MotorOps. I have replaced the turbo speed sensor and map sesnor, with no change in the problem. I have also tried several different versions of tunes being uploaded and still have an issue. I do not notice any drive-ability issues when the CEL comes on and all turbo functions seem to be normal. I have a Insight CTS2 to monitor boost but am having an issue with the boost intermittently dropping down to zero while under load and cruising. (This part is causing a bit of a loss of power and loss of aggressiveness in the EBrake but no CEL.) The two issues will happen apart from each other so both don't occur at the same time. However, I know the turbo is spinning and building boost because I can hear it spooling and can obviously feel it kick in while driving. According to the tuner they have never seen this problem in their tuning before and believe that it's a problem exclusive to my truck but I have found a few others that have had these problems but their threads seem to trail off with no real solution or anyone that has found a fix. I am now at a point that I am going to start chasing wires looking for any bad spots or connections. Just figured I would give posting on this form a shot as I have not got anywhere by posting on a few others. If anyone has any ideas at all your suggestions would be greatly appreciated. Other than these small issues I love my truck and hate having that stupid light stare at me while driving.