one thing i've noticed that's different between our buick lacrosse and my TB is the shift points. our lacrosse with light throttle will upshift and lock the converter with the rpm being as low as 1100 rpm and it will still pull and accelerate with that low of an rpm with the good old 3800 v-6 engine but the TB doesn't seem to like having the rpm lower than about 1400 or will unlock the converter. Surely these powerful inline 6 engines can handle pulling with rpm's as low as 1100 or 1200 with light throttle and not hurt them?!? that would probably help the fuel mileage too if light throttle with the rpm's that low while putting around town. the lacrosse also allows you to give more throttle to pull a hill before a downshift than the tb too which allows lower rpm to pull most hills fairly easily which also equates to better mileage. Can a tune do these changes and can the 4.2 handle it while a 3800 can with ease?