Does anyone (else) use cruise control for better MPG, and I mean in everyday driving situations, not just the highway? I just started using it on my local commute (manual '15). Not sure of the results yet, but I'm left to wonder if it helps because cruize insists upon maintaining speed obviously on small hills whereas without cruize I can back off the pedal until I crest the hill.

 

So-so. It's great on level roads, but not so good going uphill. I disengage it and control the speed myself. Going downhill, I also disengage it and take my foot off the gas.

 

My sister-in-law has owned them since the beginning (8 different new models) and says that every year the gas milage would go down. I think it's because as she's gotten older she just wines (sp) the piss out of it more, ie shifting close to redline everytime. She hates the last Fit model with the collision avoidance feature as she drives on backroads in the winter when snow ladened low hanging tree branches automatically turn on the brakes.

My 2009 says I'm getting 43mpg, but actual is usually around 39.6mpg

 

As temperatures rise from the winter, mpg goes up.

 

Can anyone guess what's going on with my gas mileage? I'm at 110,000 miles and the lifetime average gas mileage for the vehicle has been 40 MPG but the last few thousand miles have been 36 MPG. I moved back to California from Utah three months ago. I changed the spark plugs at 100k (Ruthenium). I got a valve adjustment a few hundred miles ago but it didn't seem to change anything. The auto shop overfilled the oil so I had to siphon some out, which helped make it feel less sluggish, but MPG still isn't as it originally was. Any thoughts?

 

To Gekison with the major mileage drop. those are some serious changes in your Fit, but the worst might be overfilling the oil. I make the dealer come out before we leave the lot and check the oil level, and also make sure the % number is set back to 100%.
I am on my second Honda Fit, since 2008 and now a 2019 auto. I always calculate my mileage using a spreadsheet, although I like the numbers on the dash. My mileage average over the last 5 years is 43.5, But I often get 45 mpg on certain drives at 55 mph.
I recommend to you to run your tires at 38 psi, or even 40. The ride is a bit harder, but the mileage is much better. Some guys on here run there tires at 60 psi, and that is legal. But I would never go there.

As you know, dealers might be the 'experts', but they make a lot of mistakes.