ScanGauge:
Here's what's good about Scangauge for an HX:
1) You can program a ScanGauge XGauge to indicate LeanBurn. The cryptic procedure I'll put at the end of this post makes sense once you have the SG and the SG manual.
2) Throttle position (TPS) is key to getting it into LeanBurn and keeping it there. You can read TPS on the SG. If warmed up and weather is OK and the stars are properly aligned, TPS <20 will let it go into LB. If you go to TPS 32+, it will kick out of LB regardless of other conditions. TPS 30-31 is not always enough to maintain highway speed on a New England Interstate (hills and mountains) so it can be a challenge. If I recall, max TPS on my HX is 90.
XGauge procedure to set up LeanBurn indicator:
Use the code below to monitor lean burn with the scan gauge II
To Monitor Lean Burn, type in:
TXD 686AF10115
RXF 044105150000
RXD 2808
MTH 000100020000
NAM LBN
When it reads zero you're in LB.