When I had my UIM, oil gaskets, and downpipe replaced, I also had a minor tune done to eliminate the P0420 code. I have a 2000 GT, but a 2001 GT bin file was used. The timing was adjusted a bit, and I suspect it was adjusted to premium. I've still been putting regular in, and want to keep putting regular in. I can deal with the possible P0420 code as well, as I have a OBDC-II reader that I can delete the code. So is it possible to "reflash" the PCM myself, or will I need to get a dealer to do a refresh? I know pulling the negative power will just reset all the data points.
And if a dealer has to do it, will the charge likely just be for 30-60 minutes of labor?