Actually "lean-burn" can be sustained almost indefinitely depending on the conditions you described Willie. (mainly engine load) The lean burn "window" will narrow and close with increasing speed. 72 MPHish is the top and VERY hard to maintain.  72 MPH being the VTEC transition RPM in 5th gear that will make lean burn impossible (the intake valve opening pattern changes)[end edit] 45-55 MPH is much easier. And there is that "pesky" NOx purge that will temporarily enrich the mixture and also cause lean burn to drop out.Willie Williford said:Lean Burn happens for seconds at a time, not in multi minutes.
I didn't say that at all, but it does require _technique_.NoPetrol said:You people are saying I should be getting 100 mpg at a constant 55 mph?