Hello. Yes, It's true and confirmed at least on two Explorers has this issue including mine. After My dealer did TSB in 2016, i didn't notice the smell then it's back again. i tried to seal everything in the back of my Ex and no improvement. So i had this idea and I posted this before Bad or Burnt Exhaust smell in cabin during hard acceleration. and since then this idea never left my mind so what i did is i sealed the hood rubber with silicon filler underneath the rubber " all of it" and BOOM. i was shocked i would say 92% of the smell has gone ! but i had to confirm it so i posted this. And Mr Manuel Garcia Was ready to confirm my theory, he never done any TSB with the dealer and he was facing this issue a lot and the smell was very vey bad. so he sealed the engine rubber and guess what ? Yes it worked for him too. Almost the smell has gone. then we tried another thing, covering the fresh air intake with duct tape and it also worked even better than the silicon. but this is not a solution, we can't keep the duct tape covering the fresh air intake. Now lets explain this issue, basically there are two issues. 1.Exhaust Leak from the engine side that will not appear unless there is a hard acceleration. 2. Fresh Air Intake leaks. and what happen is while acceleration the engine bay gets filled by exhaust odors and the odors finds a way to leak inside cabin through Fresh Air intake. So anyone want to confirm this go ahead and cover your fresh air intake with duct tape then go for a ride and try Careful: the duct tape is not a solution, only to confirm this leak, when you use the duct tape don't run the A\C on non circulation that might damage the A\C fan. To solve this issue permanently, The whole Fresh Air intake plastic peace need to be take off then seal every whole in it from the engine side and seal the hood rubber with silicon . but for now the silicon is working fine.