It's for sure not 3rd. When it kicks down from 3rd into passing gear does it go to 2nd or 1st. Whatever it goes to when flooring it is what it starts off in and won't shift up until going to neutral then back to drive, driving normal and it's back to shifting normal. 1st, 2nd, 3rd as it should, stop, and starts off in 1st again and shifts like nothing is wrong till you floor it again and then it does the same thing.