2001 Excursion. I read I need to hold both buttons and coast to reset the digital fuel mileage, and estimated miles left indicator. Tried several times with no change. What do I need to do?

 

You estimated miles left should be based on your tank level (need to add at least 7-8 gallons for it to recalculate DTE). Your average fuel economy should reset by pressing both buttons momentarily at the same time. It's been years since mine worked but that's what I did to reset it when it was.

If it's not doing that then there's an issue. Components on the circuit board have been known to lift causing issues (mine went blank). I'm sure having it in the roof where the sun can cook it is not the best location for a circuit board. Buying a new unit is not cheap. There are places that you can send it to and they might be able to fix it.

 

There were a number of boards with cold solder joints. You could try taking a small soldering iron and re-flow each pin on the board.

 

Todays technology is so much better that the ones used in our trucks.

You may find one on e-bay or similar. There is a company called "Reman Auto Electronics" who may have one or can repair your.

I've seen 3 or 4 towed in only to find they were out of fuel. One owners said "But, it still has fifty miles left...are you sure?". Similar to someone who told me they were getting 25 MPG around town, his OHC said so.

Better to average a few tanks around town and the same on the highway and use the odometer.

 

they are are called lie-O-meters for a good reason

i also agree about having it fixed or replaced

 

My thoughts, the lie-o meter is actually pretty accurate if reset each time you fill your fuel tank & everything is working & stock. Mine was within a couple of % of hand calculated up to the point when my fuel sender started acting up. Then the mpg remained good but the DTE went west. Then I put a tuner on & I assume that that has thrown the calculations out the window completely. HTH.