My folks have a 99 Avalon with 12 K miles (yes that right - low miles ) that has a transmission jerk. It happens when accelerating after decelerating from between 10 -20 mph. The problem feels like a delayed 2 -1 shift. The problem was there since new and at the time dealer tested it, said no trouble found. The problem feels about the same to me now and when it was new. Fluid level checks OK. Is there is a fix for this - maybe a ECU flash.
TIA