Forgive me as I am not a Zl1 owner and just stumbled across this thread, but what exactly does pulling the fuse do? I'm fairly certain if you leave the exhaust in "track" mode it will stay open regardless of driving conditions... I understand that the valves apparently close at freeway speeds, regardless of exhaust mode, but this car leaves quite a bit of carbon build up on the exhaust tips, and my inners are pristine, as if no air has flowed out. Maybe I just don't drive long enough at a steady freeway speed
