[cbaber]

If you modified the injector pulses the stock ECU would still see the changes via the o2 sensor, right? It would not like you making the engine run lean when its mission is to keep it in the ideal AFR. You would for sure need a wideband o2 sensor which isnt cheap.

I would love a custom lean burn setup. Right now on the HX its very very conservative because of emissions rules. I would love to have a lean burn switch and not have to worry about intake temps or throttle position. Just flip it on when at highway speeds. You have me researching this now!

EDIT: After a quick search it appears Greddy's emanage ultimate could do what you are wanting. Its simply a piggy-back system that uses your existing ECU and sensors and then you can custom tune a variety of settings. One of which is to tune a target A/F ratio. You would need a wideband o2 and to buy this. From a quick read it sounds like you could potentially create your own lean burn mode.