Another returning user

[Civic2000HX]

My "ride" is a 2000 Civic HX with 297,000 miles on the clock. Most recent miles were added from a round trip to Calif. and back to east Texas. The "Lean Burn" feature of this car netted fwy mileage to 40+ on multiple fill ups. Speed range fell between 65 and 70 most of the way.
One from Kingman, Arizona to Albuquerque, NM netted 46.6 mpg taking advantage of a tail wind.
I would like to hear from other users who have history with the Lean Burn of the HX and how they might have improved the mpg.
I use a ScanGauge2 https://www.scangauge.com/products/scangauge-ii/ to determine when it drops into "Lean Burn" which is an AFR of 20:1 instead of the stoiometric 15.5:1 AFR.
This vehicle re-sets a PO420 DTC which normally indicates a faulty cat con but it might be other issues. I have replaced the cat twice in the last 5 years with after-market.

[LDB]

Re-welcome. Congrats on a successful trip.

[JockoT]

An orphan thread.

[cassado10]

Originally Posted by Civic2000HX

My "ride" is a 2000 Civic HX with 297,000 miles on the clock. Most recent miles were added from a round trip to Calif. and back to east Texas. The "Lean Burn" feature of this car netted fwy mileage to 40+ on multiple fill ups. Speed range fell between 65 and 70 most of the way.
One from Kingman, Arizona to Albuquerque, NM netted 46.6 mpg taking advantage of a tail wind.
I would like to hear from other users who have history with the Lean Burn of the HX and how they might have improved the mpg.
I use a ScanGauge2 https://www.scangauge.com/products/mylowes/scangauge-ii/ to determine when it drops into "Lean Burn" which is an AFR of 20:1 instead of the stoiometric 15.5:1 AFR.
This vehicle re-sets a PO420 DTC which normally indicates a faulty cat con but it might be other issues. I have replaced the cat twice in the last 5 years with after-market.

I am also driving 2000 Civic HX and facing the same issue