HORRIBLE Gas Mileage

[thecritik]

Ok i know i've only filled it up once but what should I expect the computer in the car to read as far as MPG.

In my previous car an '04 Maxima I used to drive with a lead foot and I averaged 18.5mpg, or at least that what the computer lied and told me. I got a little less when I measured by hand.

With the first fillup, my M is reporting 14.5 MPG on the computer. Is this right? Is anyone else experiencing this. I'm hoping the previous owner used bad gas or something and the car is pissed and that eventually she'll warm up to me and the premium gas i'm putting in her and start showing me some real numbers.

Your thoughts?

[jankenpo30]

I assume you reset the MPG meter it once you got it right??

If i drive like I have some sense, I get about 18.5 in the city in M35 sport and 20 hwy doing 65-70mph. If I put my foot into it...I usually lose 1.5-2 MPG.

That's using premium gas, 0w-40 Mobil 1 & filter every 5k, knocking loose debris out of air filter once a mth & changing it every 3 mths.

[vincent82123]

I was averaging 17 MPG since I bought my 06M a month ago. After I replaced the dirty air box with Injen Intake, the first tank I got was 19.6 MPG. I didn't drive gentle after I installed the Intake and I bet the MPG number can go up in the second tank.

[Huy]

You may also want to check your tire pressure. This is a leading cause of many bad MPG.

I average 19-20 easy with mix driving.

[striz923]

i run about 16 in mostly city w/ awd. I would bet you drove a bit more "spirited" since you just got it as well.

[ghstudio]

your gas mileage will get better as you put some miles on the car...I think the engine runs rich for the first 1000 miles or so. You also should try to find gas with no ethanol...the ethanol is cutting your gas mileage by about 10%. We have a few stations locally who feature "no ethanol" gas and you really can see the difference.

[antzrus]

I have the exact same machine you have. I bought it used w/31 k miles on it. I've got 40 k now on it. I average about 12-14 in town driving very conservatively. On the highway @ a consistent 70 mph, I get about 24 mpg. I use premium about 90% of the time.

These machines are not known for their gas mileage. They all are "performance-sport type sedans" more prone to high revs and quick acceleration than low revs and good gas mileage.

I hope you researched this aspect of your machine before you bought it?

I love her, but I bought her knowing about her hi octane addiction...

[szh]

I love her, but I bought her knowing about her hi octane addiction...

Exactly right!

Z

[Q45tech]

"your gas mileage will get better as you put some miles on the car...I think the engine runs rich for the first 1000 miles or so"

Unlikely that there is even a 1% change after the first 100 miles as mixture [Air Fuel ratio] is precisely control to meet FEDERAL emission regs. Especially true of newer precision wideband O2 sensor equipt vehicles.

Now things like diff gears do wear in and reduce friction but this is primarily a initial movement [below 5-10 mph phenomenon].

After 100,000 miles ring and bearing wear can decrease friction but this is usually offset by ring wear which reduces efficiency.......usually a wash with proper oil changes every 90 days.

Oil gets thicker as it ages [evaporates and gets burned] so MPG declines minutely due to increased friction just before the change interval.

Check each of NEW EPA test and see if your driving is similar:http://www.fueleconomy.gov/FEG...shtml

Some how a 48.37 mph average in 10 minutes on a High Speed Test doesn't compute

[tigerclaws1318]

on my m45 no matter how slow i try to drive i still average 12mpg and cant get any better.

[antzrus]

I just averaged out my last 5,000 mi of driving: 18.94 mpg w/approx 40,000 mi on the machine. I'm 61 y/o and drive mildly spirited.

[zoomie]

I get just under 20 around town and 24 on the highway...been pretty consistent. I use only premium fuel.