Our Outback began doing this once in a while and now does it all the time and even at higher speeds and the hesitation is worsening ( our mileage is 171000 miles on itMy 2010 Outback has 120,000 miles. Yes, I drive a lot. Recently the car hesitates and stutters when accelerating up hills at around 40 to 50 mph. Of. Course it only does it once or twice a day and the technician can't get it to do it. He thinks it is the torque converter going in and out of lock up. Does this make sense? Anyone else experience this? He also says he has never replaced a torque converter in 20 years as a tech.