Bad mileage, bad gas, car computer adjusted??

[Bob64]

Because the car was already warmed up when you finished filling your tank.

Warmed up car = not as much fuel spent warming it up again. Also has the benefit of immediately entering Stage 4.

[J_w73]

Well I got through that tank and the computer said 54.3 , a new record for my for a tank..
and as far as distance I went 476 miles which is also a record.. last pip never started flashing
476 miles on 8.3 gallons.. showing 56.8 mpg..
and again I know this isn't accurate but I seem to always be putting in around 8.3 to 8.6 gallons on every fill up from 1 pip left..

so on the trip home on this fill up I put up a 64.6 mpg according to the computer.. another new record..

I'm not sure what is going on but I like the increased mpg..

[Shawn Clark]

Originally Posted by J_w73

so why the 61.1 mpg on my trip home with the fresh tank??

I have never averaged that much on a trip to or from work..

It's easy to get mileage that high after warm up and a tank fill depending on the remainder of the commute. In warm weather we can get 99.9 mpg for the two miles from the station depending on traffic.

[J_w73]

Originally Posted by Shawn Clark

It's easy to get mileage that high after warm up and a tank fill depending on the remainder of the commute. In warm weather we can get 99.9 mpg for the two miles from the station depending on traffic.

I guess I should have mentioned I am driving 50 miles on the freeway home..

If it is all about the car being warm the gas station is right by the free way .. so whether I stop and get gas or don't the car should be warm either way when I get on the free way.. so I should have been able to get that mileage in the past...

[TonyPSchaefer]

Here's my impression of what happened on that bad tank: you got off to a bad start. Period. That's it. Over the tank average, it's much easier to ruin a high number than to improve a low one. With the wind, the rain, and the dropping temps, your mileage will drop.

I will refer you to the <Current Mileage> link in my signature. You will find a record for every tank I've consumed over the last five years. My mileage goes down predictably every winter.

[J_w73]

Originally Posted by TonyPSchaefer

Here's my impression of what happened on that bad tank: you got off to a bad start. Period. That's it. Over the tank average, it's much easier to ruin a high number than to improve a low one. With the wind, the rain, and the dropping temps, your mileage will drop.

I will refer you to the <Current Mileage> link in my signature. You will find a record for every tank I've consumed over the last five years. My mileage goes down predictably every winter.

ok.. that is fine but why didn't I get the booming mpg that I am getting now last month when it was 90+ degrees out?.. same drive.. same AC on low.. same everything..
its been about 80 degrees the last couple of weeks..

[DaveinOlyWA]

well i have same problem except in reverse. the other day, i filled up, did a few errands and by the time i got home, i was at 75 mpg....that has dropped daily and now with 4 bars left i am at 59 mpg...it does seem to be holding.

what happened?? ... then again. never mind.

in a car that maximizes efficiency, the first thing we need to understand is that

EVERYTHING MAKES A DIFFERENCE.
* Season... gas formulation changed thru-out most of the country within the last few weeks
*temperatures
*weather (rain on the road increases rolling resistance. in heavy rain, i lose 2-4 mpg on my short trip to work)

*lights. as soon as the time changes, i will have some quantifiable numbers. not saying for sure, but it does appear that the difference will be measurable.

*and then the BIGGIE....**DEFROST**, now heat does to but to a much lesser degree. heat only slows down how fast your car gets to its optimum running temperature.

but like i said, everything makes a difference

[EZW1]

Originally Posted by qbee42

Cold weather and fuel formulations could easily account for your mileage variation.

Tom

Yup. I was easily getting 63 t 65 on my '09 but this morning the temp was down to 50F and I found I had to finesse the car to maintain 63. If this winter is going to be like last winter, then when it gets colder I'll be lucky if I can get 55.

[DaveinOlyWA]

Originally Posted by EZW1

Yup. I was easily getting 63 t 65 on my '09 but this morning the temp was down to 50F and I found I had to finesse the car to maintain 63. If this winter is going to be like last winter, then when it gets colder I'll be lucky if I can get 55.

u have "winter" in Phoenix?

[TonyPSchaefer]

Originally Posted by J_w73

ok.. that is fine but why didn't I get the booming mpg that I am getting now last month when it was 90+ degrees out?.. same drive.. same AC on low.. same everything..
its been about 80 degrees the last couple of weeks..

Here's your answer.

Originally Posted by J_w73

ok.. I've had my car for about a month

Give it time, young padawan. The reason you are turning out record tanks now is that you are learning about driving the car and the car is learning about how you drive it. Shoot, I didn't crack 55mpg for almost a year.