The car:
2006 350z Touring 6spd Roadster
No engine mods (put a K&N drop in about 20 miles ago).
a little over 21k miles.

I just bought the car recently and have noticed a consistent fuel economy of 11mpg. My work commute is very short (1.9mi each way)x2(for lunch).
Took the car to the dealer yesterday. Had them start the mark off process for the engine oil consumption problem (I think it's eaten about a quart of oil since last oil change). I also had them try to diagnose the fuel consumption problem and they said the A/F tests came back 100% with nothing wrong. Anyone else having this problem? Any ideas?

 

According to Nissan having to add one quart of oil between oil changes is normal......

 

Doing alot of short distance driving is supposed to be bad for your fuel economy but only getting 11 mpg sucks.My commute is about 3miles and I get 17-20 mpg.

 

My commute is 2 miles and for that part I'm only getting 13-15 mpg.

 

Tire pressure?

 

what RPM you shift at? Do you drive in a higher gear? City driving or highway? I am guessing city since you have such a short commute.

 

wow this time of year is bad for fuel economy. look at my post from earlier today on this same forum. check your tire psi. check your airfilter and make sure it's not cluttered with leaves. how long have you owned the car? a 2 mile commute is terrible for fuel economy considering the car will run rich until it's warmed up. take the thing out for some long trips and give it some throttle to wind out the gears and clean out the motor! switch to a different brand of gas the next tank and make sure it's premium grade.

 

i've been noticing bad fuel economy as well....i've been getting 15~17mpg city driving and now i barely go 12 mpg...

 

I wonder if this directly related to dropping fuel costs. MTBE's in our tanks?

 

Post a photo of your MPG guage.

 

I've been averaging in the 15's recently. Read the thread on winter gas.

 

I use 93 grade fuel ONLY. Mostly city driving, with a quick .5mi trip getting on a light highway - more like a 3 lane road w/ average speed of 55. I shift around 3k rpm. I stay in the lower gears (1,2,3) on the back streets and get up to 6th gear on the highway.

Tire pressure is normal (Checking the psi today it was 33 all around).
Air filter was recently changed about 30 miles ago and all leaves pulled out. (No difference).
I'll try to post up a pic of the guage tomorrow night. Guage is reset after every fill up.
Last fill up after 140 miles, was 11.8 gallons of fuel. Which approx equals 11.9 mpg.

I have been recommended to take the car out for a longer drive. I will hopefully try that this weekend.

 

If you get your gas from the same place consistently, try going to a different station of a different brand.

 

I notice a huge difference in city vs highway mpg. Think that's just how the z rollz

 

My g/f has a new 2008 Civic Si and she has approximately the same work travel as you do. About a mile to work, home for lunch, back to work, then home again. She averages about 21-23 mpg on those short drives. Though if she does a mix of highway/city she averages 26-28 and strictly highway she gets 37+. Regardless, those short drives kill gas mileage. Though 11mpg does seem a little weak.

 

I've actually already tried 2 different places for gas. No change.

 

drive to AC and back and let us know if your mpg doesn't get closer to 20mpg

 

I could, all that proves is there's more than one way to empty my wallet.

 

I would attribute your poor mpg to the short distances you are driving.

Engines need to run rich when it is cold so that it will start quickly and not stall. Anything with a carburetor will have a choke to do this (lawnmowers, boats, motorcycles, weedeaters and virtually every car made between 1900 and 1990). Modern cars do it electronically. Everybodys Z gets crappy mileage until it gets to operating temperature.

So someone that drives only 2 miles per trip will surely get crappy mileage.

Try this. Watch your temp gauge. How much of your 2 mile trip is at normal operating temp? The answer doesn't matter, but just be aware of how much of your driving is done with the engine cold.

Also do this. Go out driving for a few miles. After you get up to normal operating temp, reset your trip computer and drive a couple of miles while warmed up to see how the mpg calculates.

 

will do, you're the second person to say that. I'll post pics up tonight to prove my mpg when i get home from work.