Hi all,

I have a 2007 base AT Fit with about 22K on it. Only thing that isn't stock is the radio. The first 20K was put on the car in New Orleans, LA. I averaged roughly 28-32 in the city, and 32-35+ on the highway. I moved in late June to Denver, CO. The MPG on the drive up was normal.

My first full city-tank in July was 24MPG. I thought this was my adjusting to driving in an area with inclines. Each tank after that declined. After three fillups, I was pulling 19 MPG. The oil level is fine (both gauge reading and a manual test). The air in the tires were low, and I filled them up to 45 PSI like I normally do. The tank after filling up the tires was 20 MPG.

I have not been driving as much here (walking), and most of my trips are relatively short (5-7 round trip). Gas, even getting bad mileage, is lasting weeks between fillups. Any ideas what's causing a massive dropoff in my MPG?

Thanks in advance.

 

Check the the air filter? Spark plugs? etc. Routine maintenance stuff.

 

Just a wild guess but I wonder if you need to re-set the computer so it can adjust to the higher altitude? You might also be giving it a lot more gas to compensate as the engine will make a less power than it would at sea level. You might also try to find out what mileage other Fits are getting in Denver.

 

I think the air filter was replaced right before the move when I had routine maintenance done right before the move. I'll have to check the receipts. Still at 40% oil levels and no maintenance codes. Don't really have the time to check under the hood until at least next weekend though.

How would I reset the computer, just disconnect the battery?

I know that some of it is due to me adjusting to driving in not-flat areas, but it seems way too low even with that. I ran into someone at the 7/11 that had one, he claimed about 26-30 city on the AT (2008).

Thanks for the suggestions guys, I appreciate it.

 

You pull the battery or ECU for a certain period of time. Make sure if you have the stock radio you have the unlock code ready. What's the % of ethanol in the fuel? That usually dictates some MPG too.

 

Ethanol is 10%.

 

I would say the biggest factor is altitude. You moved from sea level to + ~1 mile above sea level.


And an ECU reset should help with that. Disconnect battery I believe. I believe you must also let the car idle upon first start.

 

I checked the plugs, air filters, fluid levels, etc. Everything looked fine.

I'm going to try the ECU reset in a few days and see what happens.

 

Make sure you have your radio code if you are still using the stock radio. In addition it will take a day or two for adjustments to be made to your ECU but after that it should be smooth sailing.

 

This thread was helpful for me, good instructions on how to do the reset.

https://www.fitfreak.net/forums/fit-...procedure.html

 

Just an update, I did the reset about two and a half weeks ago. I was at about 50% on the fuel gauge. MPG calculation after filling up last week was a slight improvement (23 MPG). Will post the results of the first full tank when I fill up next week.

 

Hmm. I have a 09, but maybe someone is stealing your gas?

 

I actually thought about that possibility. I started taking a cellphone picture of the gas gauge when I'd get out of the car to check. If someone is stealing gas, they aren't taking enough to move the needle.

 

haahaha my friends dad used to steal his sons gas... he would fill up in the morning and when he came home the gas was like 1/4 and hes dad said he didnt take the car out hahaha

 

meh! it might, a bit... but the ECU is adaptive, meaning if he's been driving there for a while it should've already gone through and optimized itself to the best of its ability.

I don't know how it works with hondas but all the other cars I've dealt with have relied on just pulling the negative battery cable for the ECU to reset (I only mention this because intuitively, I would've only pulled the positive cable).

reguardless, you have something at issue and a drop of that much is a concern... unless you are driving in very hilly terrain, thats the only explanation I can think of. Start paying attention of where your RPMs spend the majority of their time.

 

What's your point?

90% gasoline with 10% ethanol gives you 3% less energy per gallon.

If he was getting 30 mpg city the most he'd lose from going from straight gasoline to 90/10 would be about one MPG, not 10.

 

true, but it can contribute. if the op can find one more small thing like that, plus the reset of the ecu, he/she can hopefully have the full mpg potential.