Need help on what you guys think this would be My 2011 Suburban had P0121 code that would turn on and off . I was on a road trip and the the Suburban started to have a slight hesitation while accelerating, but not at shift. I cleaned throttle body, and had a 3000 rpm while at idle. Reset the throttle and it went away. But took it out for drive and had a jerk when coming to complete stop and before taking off, almost like has a delay in shifting . After a few days of trying to drive it to see if it would relearn it added another issue. I put it in reverse and wouldn't go into gear until I pushed on the gas for a few seconds. I changed the Throttle position sensor, but didn't work. Disconnected the battery for a day. Do I need a new tyranny? Any suggestions would help if anyone has had the same issue. Thanks.