I second the cowl issue (if you have one). This happened to me on my Sukhoi, ran good on the ground but once I got into some hard flying it would bog down and die after a few minutes from over heating. I have a TT Pro46 on it, my friend has the same plane with the same engine and it did the same exact thing. It took awhile but I finally got it right. I cut the cowl out a little more, and it took some needle valve tweaking. Good Luck, I know its frustrating.