In a "165 ECM running 6E there is a scalar titled "IAC Steps Added to T/F in Drive", what is T/F?

I'm just wondering. To be honest I'm about sick of playing with this obsolete ECM. It was fine with the old engine which had a smaller cam but this 280/288 XFI cam has proven to be a real pain to get it a driver friendly as I want it to be.