Diesels don't like heavy throttle at low revs, tuned or not. Although diesels normally have torque at lower revs, they don't like to lug under throttle. Excessive throttle at low revs just overfuels the engine and bogs it down. At low revs the turbo doesn't spin enough to give enough boost to match the fuel going in.
My 2013 auto D4D DC SR5, prefilter, 3" exhaust and Chip with egt probe, stock SR5 rims with Toyo Open Country AT2 265/65R/17's