I think much will be revealed by logging. I hadn't even gotten my tune straightened out by 150 miles. It took a while.
I wish there was one single thing i could point to but i had a confluence of things fail on top of each other so there was not one single thing.
If i had to guess, the failing Big Wheel Turbo was probably the culprit and while i replaced other things trying to fix the issue, I should have just checked the turbo earlier and saved myself a lot of time. When i finally did (in my case) it was really obvious it was fried. The second turbo i caught much earlier because i had gone through similar (but not exact) issues with the first one.
I could tell you to mess with the waste gate rod length but I won't. In fact, I strongly recommend
not messing with that without the help of your tuner as it could be very easy to go too far and just create further issues. It "might" be that, it might not but working with someone that can view what is happening and guide you while you are doing it would be my recommendation.
I know when i switched back to my OEM K04 and had Trifecta re-tune it for that with the Bosch sensors and Solo Hi-flow CAT and exhaust, no more sputter.
But i did miss the WOW factor of the Big Wheel. After all the messing around I have done I will echo the sentiment some others have put out here.
-If reliability is your #1 goal, I think the stock Turbo with an appropriate tune for the rest of your bolt ons would be a wise choice. (just my opinion).
I dont think the rest of your bolt-ons really stress the motor at all and are worth keeping.
On the other hand just about every hose, sensor, clamp and tube is now brand new on the car... So i guess that is the upside for me?
I certainly know more about the motor than i ever planned to
And now that I haver had a taste of the BW turbo, the OEM just wont satisfy. I am, however expecting the trade off of more work on the car than if i left it stock.