With my other 3 automatics (2 Full Size Broncos, F250 Diesel), I can pulse and glide (40 to 55, then back down) by shifting to neutral, then at 40, shift to drive, repeat. I also neutral coast A LOT. Between my wife and I, we found good results from 55 mph, to coast down to 25mph before touching brakes at the stop sign. I'm sure others will go much lower than that. It takes some timing to find where to shift to neutral to be down to 25 or so coasting to a stop sign.
Neutral-coasting these gas guzzlers has netted the most FE gain. Unless your car coasts forever in Drive, you should really reconsider neutral-coasting with the engine ON. Watch the
Scangauge and see what it does for you.
That
Scangauge you got will teach you lots at where you can improve your MPG - enjoy!
PS Also you ought to consider adopting a self-imposed 55 mph speed limit...