Our 2019 Journey GT is acting the same but only after engine is heat soaked. When engine/drivetrain is cold and starting to warm up, it accelerates fine. I assume these 3.6's do not perform well under extreme heat. 100+ ambient temps, and the 3.6 performs pretty bad from stop. Not sure if it is engine or transmission that is causing the lag. Almost feel like the traction control kicks in to prevent car from losing traction from a stop. Cold seasons, the vehicle performas normal. Just do not like the hot temps outside.
