The only things I can suggest is either a completely clean install of X-Plane or thoroughly go through your assignments for mixture and throttle.
There is nothing that should be causing this, least of all an add on loaded prior, somehow, corrupting the code that controls the throttle, and judging by your log, with all plugins taken out, I'm almost 100% certain it is some kind of key assignment that is overriding your mixture or throttles. I've just tested a fresh install of the TBM on my PC, and all is working as it should be. I've asked other people who have a steam copy of X-Plane and they also said everything is working fine.
I don't want to ask you to do a fresh install of X-Plane, but if we can't narrow this down, I'm afraid it may be the only course of action.