Poor gas mileage

Do you have a dealer level scan tool? Without it and a programming box and subscription to the Honda programming site, what you want to do isn't possible as there are no ways to reset the PCM in that truck without those items.
What mileage are you getting at the moment and did the mileage suddenly drop around late September? Keep in mind it's rated for 16 city and 20 highway and if you are in an area that blends fuel for the winter it can drop by 2mpg easy. Any changes in where you get gas? Check engine light on?

I'm getting 13 MPG and have been for more than a year. I think California does change the fuel blend each season. I use Chevron religiously and have seen a decline as I said over the last year or so. No check engine lights, runs smoothly and has a good set of Michelin LTX tires. I'm having a tug of war with my sensibility right now to either keep the truck or buy new but for a 13 year old truck with 89,000, I can't bring myself to spend the money. It sounds like I might be asking for a miracle. Many have posted that they disconnect their battery for 10 - 15 minutes and then do a re-learn process. I was thinking of trying this. After reading these posts, I thought it might have been possible that this began after changing the battery 17 months ago but I may be just grasping at straws. Any other thoughts?

Appreciate the response!!

Hello,

Here are some ways to reset or clear codes out the (MICU) Module. Please check out the attachments before you start.

Gauge Control Module DTC Display

How to display DTCs on the gauge control module
While in Test Mode 1, the DTCs which have been detected and stored individually by various B-CAN (Body-controller Area Network) units, will be shown one by one on the multi-information display when the communication between the Multiplex Integrated Control Unit (MICU) and the gauge control module is normal. To scroll through the DTCs, press the select/reset switch on the gauge control model.

The unit that has been stored the code can be identified by the number shown on the multi-information display.

How to clear DTC
While in Test Mode 1, press and hold down the SELECT/RESET switch button for more than 10 seconds.
You can disconnect your battery Too completely clear the PCM diagnostic trouble codes. Remove both positive and negative battery terminals and clamp them together for 15 minutes. (Note; This procedure is not recommended, It can erase idle learn and radio settings you have saved and any other accessories that use memory).
Please let us know if this information was helpful and if it corrected your problem.

Thank you
Joe Terwilliger

Disconnecting the battery only clears items that wouldn't really alter fuel mileage. Namely the idle learn and things that are personalized. When was the last time it had a tune up? Have you changed driving style or distances in that time? Like going from a 10+ mile trip to something like 3-4 miles? Or using a hilly route from flat? When is the last time the transmission and axles were serviced. Was anything else changed prior to this issue?