My car is 2011 toyota vios with 1NZ-FE mated to 4-speed AT.
Recently I notice that when the car is speeding up from 15km/h to 60km/h while the gear is at the point of time in 2nd or 3rd position, the moment I let off the throttle pedal, RPM needle will drop fast from 2000+ RPM to around 1000 RPM then surge a bit up to around 1200 RPM. I can hear there is a minor shock noise from the front and feeling a little bit of jerk.
While the gear is in 4th gear, either lock up or not, letting off the throttle pedal, RPM will just reduce slowly which I feel this is normal.
What are the possibilities of the problem?
Rpm drop fast after letting off throttle pedal