Thanksphoebeisis for the info on the pulse and glide. That's what I've been doing the last couple of years driving and have noticed a measurable increase in fuel economy. I usually pulse up to about 40 to make sure it gets in to OD. According to other GMTC forum members an electrical cooling fan system is one of the best ways to increase power and efficiency. There are several write-ups and posts that deal with that. One of these days I'll get around to doing it on my 99 Suburban.