My friend is buying a 99 Silverado with the LQ4 6.0L. Does anyone have any suggestions what we can do with it, tune wise, to improve mileage and maybe some responsiveness? Not looking for anything crazy (and I know tuning alone can't really net a ton in a gasser). I know a little about tuning diesels, but I know zip about gas motors.
We haven't gone to pick it up yet, but does anyone know what PCM is in it? Is it the 0411 or something else?