Car started acting up, seems to be more in stop and go traffic. When the car downshifts from second into first there's a noticeable lurch. Seems to be doing this fairly consistently.

Yesterday I was noticing the lurching downshift as I was driving downtown Toronto. When I went to pull away from a set of lights the car refused to shift out of first (5000 rpm doing 40kph sucks) I went through two lights like this and pulled over. Disconnected the battery to reset the computer and tried again, and it was shifting fine.

So I'm torn, is a Tranny issue or is it more likely to be my ECM? Or the Tranny computer perhaps?