Disappointing 2nd tank mileage

[sig808]

I just filled up my second tank and I was disappointed to find that my second tank mileage was only 36mpg. This is down from 41mpg on my first tank. Granted, on my first tank I did much more hwy driving.

Anyway, I think some contributing factors were:
1. (Before reading the boards) I filled up with premium gas, instead of regular
2. The past 2.5 weeks I was not using the Auto AC mode and just left the AC on. (It's been kinda hot recently).
3. More city driving
4. Car is still being broken in, just passed the 600 mile mark

So, I'm posting to get some words of encouragement that my I2 will rise like a phoenix from the ashes and get back to the 40+ mpg mark again!

Any ideas of what else could have contributed? My driving style was pretty similar. I'm hoping that the MPGs get better as time goes on. Is this what you have experienced?

Oh, I'm also getting my windows tinted in hopes of working the AC a little less. Seriously, it's getting too darn hot now days. Thanks in advance!

[WFalicoff]

I believe that you will get better mpg using the lower octane gasoline for an engine designed to operate at the lower octane. This was a car radio show several years ago which stated this. The expert claimed there was more "energy" per gallon in the lower octane gas. This I remember was counter intuitive.

There is an improvement once the engine is broken in. Also, using the AC full on really hurts mpg. I have tested this out on several occasions. You should also check the psi on your tires as this makes a big difference. Finally, your driving technique makes a huge difference in mpg. I can go from 40mpg to over 60 just by altering the way I drive the car and the AC setup (eco mode versus drive). You can hone your skills by using the color indicator and set the gauge to show you the instantaneous MPG. Try maximizing the time you are in the green. Slight changes in the pedal pressure can change the mpg by as much as 10mpg, even when you think you are driving at a constant velocity. Also you want to coast as much as possible. There are other tricks you can learn by others on this site (what speed to drive in the city, etc). The highest mpg I have ever achieved is 72mpg going at an average speed of 65mph ove a distance of 35 miles (I was not even in econo mode when I did this!).

I expect you will see at least 43 mpg once the car is broken in and you hone your skills a bit, even driving in the hilly bay area of CA. My wife gets a min 41 to 44mpg driving from Los Angeles to Southern Oregon at 75 to 80 mph with the AC at max output. She drove back a short while ago in triple digit temperatures and got 44mpg without any concern for getting good mileage. I hope this helps.

[mikept03]

This sounds reasonable to me if you've been using more A/C. I've also noticed that A/C use really hurts the mileage. I've been getting as low as 35mpg in suburban driving now that it's heated up outside, though I also drive to keep up with traffic and don't like sweating it out at lights. Mileage wise this car really exceeds on the highway more than the city. In highway driving I can keep up with traffic (barely) and fairly easily top 50mpg.

[Cobb]

Id go back to regular gas and keep econ on and in drive. I bet a non hybrid car would of gottwn close to 15mpg in those conditions.

Did you check your tire psi? I run 44psi myself.

[fuelmiser]

Yeah, running premium won't make a difference.

I have almost 13,000 miles on my car now and I just took a trip to a friend's house over an hour away and from door to door I averaged almost 52 MPG. Glad I got the Insight instead of paying $10,000 more to get a 2010 Prius. My MPG isn't much lower than the Prius.

If you read some of my earlier posts when I first got my car, I wasn't all that happy with the MPG as well. It's like they said, you have to wait for the car to break in.

Every 4,000 miles I put in Amsoil P.I. That cleans out all of the carbon so that I don't have to put in mid-grade or premium fuel. You'll notice that many people start to have their engines ping when they put high miles on the car. That's from the carbon building up inside the top of the pistons and cylinder head. The carbon can cause pre-detonation. People will run higher octane to combat this. The solution is to get it cleaned out so that you don't have to keep running expensive fuel all the time. You won't have to worry about that now, but that's something to think about in the distant future. When I order my oil for the year, sometimes I'll buy 2 to 4 bottles of that stuff and keep it on the shelf until I need it. Every person I've ever talked to in person tells me they love this stuff. I use it now for preventative maintenance.

I was thinking that my car was sort of a gas hog. (I'm getting spoiled.)

Then I went and drove another car for a while and had to fill the tank. I was all pissed off when I had to pay almost $45 to fill the tank to drive the same distance I'd normally go in the Insight for $24-26 worth of fuel. Now I am so glad I have this car.

I was thinking about trading it for another car. After I filled up the tank in that other car, I changed my mind REAL QUICK.

At least the Insight II's are not really slow. They have no problems keeping up with traffic or passing people. I'm still pretty happy with the car so far.

If any of you are starting to get tired or bored of your Insight... trade cars with a friend for a week or two and go back. You may change your mind real quick and appreciate what you got. I know I did.