What rpm is your engine running @ doing 80 mph?
Leanburn will not activate if the engine is above the vtec-e engagement point, with both valves opening there isnt enough swirl inside to support uber lean mixtures. When driven above the vtec point the engine will return FE like a normal civic.
My hx has a EX tranny and I can only use leanburn to about 65 mph because of my shorter gearing.
One thing about leanburn is that is dislikes any rapid increase in throttle. In fact I read an article about someone who made a circuit to smooth the tps voltages the ecu was seeing and on the Insight it worked pretty well.
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