ive had my car for all 118k and i have always been playing through the gears upshifting and downshifting. one tranny was replaced at 45k and thats it the 2nd one is lasting. the first one was replaced b/c it had a delay shifting from 2nd to 3rd.

u can shift from d4 to d3 without pushing the button but from d3 to 2 you need 2 push it b/c it is locked same with 2 to 1.

how old is the car? routeine maintanence done? how many miles?
it might have misfired or it might have nothing to do with the engine. get the codes checked and get back 2 us