I have a 2008 GT 500 it has about 4500 miles and I have taken it in 3 times to get it tested after the first test I was told it needs to be driven more so I took it on a 400 mile trip, but it still says the cats are not ready as well as the 02 sensors. Any ideas oh it has flowmaster mufflers but is otherwise stock.
Could you please elaborate on this because not much of your post makes any sense other than the title.