Loss of power in 3rd gear 2012 Eco 6spd manual

This is a somewhat random and odd occurrence. It tends to happen either when the car is not yet fully warmed up or after a long drive when it has been sitting for perhaps 2hrs. If I allow the car to fully warm up prior to moving I have not found this to happen. Anyway...when it does occur it happens in 3rd gear...the car acts as if fuel is completely cut off. (Major bucking) This is a 2012 6spd manual Eco. Even if I take it out of gear when this happens and tap the pedal it sometimes will not respond. I've already changed the throttle body and accelerator pedal assembly. The only other thing I can think of trying is replacing the MAF. I do not appear to have any check engine codes thrown by this...however I do need to replace the downstream O2 sensor. Not sure if that could somehow be involved in this or not. Any ideas?

FYI...358k miles...yes...that's not a typo. Original clutch...I just finally put a real chunk of money into it recently...had to change the timing cover gasket due to a major oil leak so also changed the chain, guides etc...and then the oil cooler crapped itself so had to change that and decided it made sense to replace the turbo and exhaust, as that was not long for the world. Glad I did the turbo as there was definitely some shaft play and I had the under boost code due to the typical crack near the wastegate.