So here’s the run down, I feel as if my g has tranny problems because sometimes, not all the times, I would come to a stop and it downshifts like normally but when it gets to the “last” downshift it jerks me as if I got hit from behind, then my rpms stay at 900-1k, then when that happens I go to accelerate and it like “jumps”/pulls me back as if I pressed on the accelerated hard, then it stays at around 2k rpm won’t shift and it goes slow so I have to press on the accelerated a little bit more till 3-3500 rpm then it shifts, it’s auto btw and has 128k miles 08 g37

 

When you shut the car off and restart it, do the RPM's return to normal @≈650rpm?

My '08/5AT exhibited the same jerking/high idle issue when braking. All would be normal then suddenly this gremlin would pop up. Infiniti issued a technical bulletin for this which required a ECU reflash. I had mine done about 8-10 years ago and have never had a idle issue since. I don't know if your erratic shift points are related, but this should at least get you started.

ITB 07-048B pdf

 

Yea they return back to normal, but how do you do that ecu re flash ?

 

Edited title to something more meaningful....