Just got an `10 XFE Cobalt (5spd)

[bigmarky]

msrp was 16k, out the door 10.8k
30miles on the odometer when i bought it


first tank of gas...
cpu said i avged 38mpg
receipt calculated to 35

2nd receipt 35
cpu avg 36

3rd receipt 34
cpu avg 35

4th receipt 31mpg
cpu avg 32

WHAT THE @#$#@$
I'm losing mpg doing the exact same drive everyday

I drive 65-70, its a long flat road to work, with mild city mixxed in, but all redlights

I coast to the reds in neutral

my xfe had a gas cap problem, but they replaced it
do u think i should just reset my cpu by d/c the battery for 1hr or so

I'm getting lower and lower and its driving me nuts.

[Weather Spotter]

What are your weather conditions?
Cooler weather can lower MPG.
rainy weather can lower my MPG 2-4.
Using defrost setting turns on AC that could account for all 4MPG.
Winds can also play havoc with MPG.

How many days in between fill ups?

[bigmarky]

tires are at 32psi all around
weather is pretty strong out on the open road
the xfe doesnt go straight very easily with the winds

weather is very damp/humid 80-85 in the morning

no defrost but ac is on -
its been on everyday -

so that is not the variable in terms of going from 38 to 31

i thought u get more mpg with cooler air
the air is more dense, and more o2 molecules in the air

air + gas = boom
more air = less gas needed

[IsaacCarlson]

Gas burns at a certain ratio...14.7:1
The more air you suck in, the more gas you HAVE to put in.

[Weather Spotter]

cooler air is more dense, so more aerodynamic resistance to overcome.

Winds can play a big roll in that MPG drop. At highway speeds high winds drop my MPG anywhere from 3-10 MPG. Wind is also always changing direction, so the first day or two it might have been helping and now it is hurting you.

[Fr3AkAzOiD]

It will be better with break in.
I had the same issues when I got my '08 XFE.

Put a lower grill block in (so long as coolant temps don't go over 210), slowly pump up your tires (add 2 psi to your tires every other tank till you hit 40 psi cold) and by the time you hit 10,000 miles you shouldn't have any problems breaking 40 mpg so long as you keep your foot out of it.

This site was the most help for me and starting a gas log is the beginning of it but another resourse you may want to check out is yourcobalt.com
There is a mpg section in the forum and since they deal with just Cobalts there are a few people that can help quite a bit.