^^Once you have reset all the adaptations I would also retrain the car by driving it hard occasionally or drive it in manual shift mode occasionally. The lag/surge behavior you reported is related to the throttle. Others who experienced it have said it goes away over time. If you keep trying to test the problem, you will, in fact, keep recreating it because of the way the throttle adaptation works. So, try the opposite tack of teaching the throttle how you want it to behave. This usually means not stabbing the pedal. Manual mode driving, sport mode driving, medium throttle driving as opposed to babying the throttle then mashing the throttle.
Also, chip tuners that don’t void the warranty, as mentioned elsewhere.
Also, chip tuners that don’t void the warranty, as mentioned elsewhere.