i was on my iphone, lol, i typed retune, it corrected with refund, lol.
ya, the retune would be guessing.
the ltrims aren't +25 or -25, so that tell me the fueling is pretty darn close.
plus there isn't a lean or rich condition code being set.
if i send a retune out, i'll need some sort of baseline first, so scanning was mentioned so we can fine tune the truck.
timing is always pretty close or dead on; that is based on what certain trucks like.