The car is an '08 Sport (5dr) with the EJ253/4EAT.
When decelerating to a stop there's a pronounced clunk on the 2-1 shift. Feels like gear backlash or a bad mount. It's repeatable and does it 9/10 times.
Decelerating into a tight corner it will hold 2nd until I *lightly* resume accelerating at the apex. It will then thump/shudder into 1st and spike the RPM where it should (used to) hold 2nd and casually accelerate. This is also repeatable 9/10 times.
Accelerating at a normal pace in "D" I sometimes notice hesitation in 2nd gear between 2200-2500rpm. It will either upshift right to 4th/OD which lugs it down or upshift to 3rd, then drop back to 2nd, then 3rd, 4th/OD. Running the AC exaggerates the problem. There's no hesitation accelerating "Sport" and no issue in either mode if I give it more throttle but that requires a faster pace than the flow of traffic.
ATF is a golden brown colour, level is good, does not smell burnt but I don't know the history if it. No issues shifting between P/R/N/D. Grounds are good, battery terminals are clean and tight. Plugs, valve cover gaskets and tube seals have all been done within a year. No codes.
Clearing the ECU and relearning the throttle helps in the short term but it eventually goes back to it's ways. Valve body? Crank position sensor Dirty injectors? Reflash? Just the way it is? I'm at a loss.