No it won't change the reading what they where saying is you can get every last drop out of the tank. Would you rather the light come on right before you run out? Every GM I have ever owned the light comes on with a least 4 gal left.
No I don't want the light to come on right before I run out but it's kind of silly that it tells me to get fuel when I still have just a tink over 23% (6 gallons) of fuel still left in the tank. Now I do know that it’s not good to run out of fuel in a diesel but maybe the light could be set up for more like 8% left in the tank.
Does your DIC tell you that you have 400+ miles when you fill up but the best you can get is 330 if so then I guess mine is normal to be off a 100 miles or perhaps when I bought the truck it had a 6" lift with 35s and that is throwing it off but there’s no way to fix it. Because I bought a Truespeed Calibrator thinking it would also fix my light and miles adjustments but it didn't.
If all the sump does is get every drop Dozerboy then what would be the purpose of that? What's wrong with the 4 gallons thats left over you'll just go to fill up and be on your way. I just thought it would fix my problem with the DIC somehow because it drives me crazy. My bad!