[brucepick]

Today is my first time viewing this thread - most interesting!

My HX is a '97, the generation before darcane's HX. I expect much of the lean burn control logic in darcane's HX is the same as on my car but I can't guarantee it.

Anyway, I have a 55 mile jaunt to work daily. For the highway, I've settled on a blend of Lean Burn and pulse-and-glide. Details...

I don't kill the engine (usually) since that requires 1.5 to 2 miles distance under power to make lean burn available again. I pulse the engine at the max throttle I can, without losing lean burn. I do that till it reaches my upper speed limit - somewhere around 70 mph. Then neutral coast till speed drops to my lower limit, around 50-55. Then back into gear, baby it just right to get it into lean burn, then max allowable throttle again.

I use this principle pretty much the same, regardless of whether I'm going up grade or down. Going up, it takes longer to reach maximum speed, and I may never reach it. Going down, it only takes a few seconds to reach max speed before I put it in neutral for a nice coast.

I have one coast over a mile, shortly before exiting the interstate. I do kill the engine for that coast, and then use a more conventional EOC with engine shutdown the rest of the way to work. No sense in preserving the lean burn capability if I'm getting off the highway anyway.

My MPGuino is very good at measuring fuel use even with a lean burn engine. It's nearly always within +/- 0.2 gallons when I fill up, often within 0.1 gal.