Went from Albuquerque NM (elevation 5300ish feet) to Devils Lake ND (elevation 1400ish feet) and noticed that I'm getting about 14-16mpg instead of the usual 20-22. I've cleaned the air filter, the plugs/cap/rotor are all new and other than the IACV being busted (idles high at start up) everything works great. What I'm wondering is if there is something I needed to adjust when changing that much elevation and going to an area with more moisture. I'm guessing the ECU does all that but wanted to ask anyway.

Thanks for your time.

 

You shouldn't have to adjust anything, even if you do need to, 6 MPG is a crazy difference. Now I know what to say to people asking for gas saving tips, "move to Albuquerque, NM" Seriously I have no clue. Is that a Motorcycle bar riser on your profile pic?

 

At 5300 feet the air is less oxygen rich. Less oxygen=less fuel burn. I have the opposite scenario. Moved from the Oregon coast to 5000 feet in Colorado. How long have you been at the lower elevation? Sometimes it takes some time for the ECU to adapt. Have you tried disconnecting the negative batt cable to reset it? Just my 2 cents.

 

I would put an ohm meter on the O2 sensor to see if it's working properly. The O2 sensor is the only circuit that tells the computer how much fuel to add to make the fuel trim correct...well besides the cold start injector time switch on start up. The element in the sensor might not be heating and in turn is telling the ECM to add fuel?

Just a thought, but that is where I would start.

 

Ball joint spacers.

Good idea on the o2 sensor. Shouldn't have to *adjust* anything.