GMC Yukon XL 2004Change

We've owned our '04 Yukon XL 4 years now. The LS motor is superb, one of the best engines out there. Built to last, with things like factory stainless steel exhaust that will never need to be replaced.
The fuel economy, however, is horrible. Nothing we try will get us above 20 mpg (IMP) highway.
The ride is superb and never gets tiresome, and the power from a relatively small 5.3 liter engine is surprising. The cargo space is unmatched, tons of room for my family of 6 and all of our luggage. I have even carried a large 12 foot roll of carpet inside with all the doors and hatches closed, something you can't do with a full sized pick-up.
The memory seats don't remember positions well. The electronic auto 4wd control is wonky and has tried to switch to 4LO unexpectedly while driving highway speeds on at least 3 occasions. The front differential seals leak and are a common problem for this generation of GM. The ABS brakes are acting up now and pulse every time we use the brakes, even on dry pavement. Aside from numerous little aggravating quirks that are common to this brand, we like the truck overall. But only because of the high fuel consumption, I will never purchase another one.