Well FIRST OFF i would really like to apologize for starting a new thread this has been discussed before.... but I really tried researching and asking at least 5 different mechanics about this issue.
My problem is that once I get a full tank and drive on highway for most of the time (80% highway). I only get about 278 miles off the full tank... I know i bought a meaty engine and it kills gas... but seriously I think its a major problem if i drive under 2000 rpm and stay cruise controlled on 65mph crusing mostly on a straight aways. In city driving its worse... i drive for less than 20 miles and i loose 1/4 of my tank. I have already tried doing a lot to increase gas mileage. I JUST BOUGHT THIS CAR and it came with brand new tires, i did another oil change putting mobil 1, and Im using a K&N filter now. All my mechanics give me some bull**** answer and just say "you drive a 3.5 liter of course it kills gas." I personally know this is a problem and they cant check it unless CEL is on x.x so i was thinking about taking it to the stealerships and letting them rob me. But before that i would seriously hope i can get some tips or help before i go suicide and lose my pride there. BTW my mileage is 48k. THANKS IN ADVANCE.

 

bro. i get 230/240 miles per tank.

You're lucky you can get more than mine.

 

It all varies among our cars. I'm not sure exactly, but I think I get in the ballpark of 300-350 per tank, and sometimes 400 when it's all highway. But that was when I was living in Florida, idk now since I'm living in Texas...

Check out this thread, maybe it could help somewhat:

https://g35driver.com/forums/g35-sed...s-getting.html

 

i read that thread.... it dont really help me much lol i did the oil change and got a new air filter but i didnt see any gains at all.

 

driving style is a BIG factor in your gas mileage.

tire pressure too.

dont know ho the K&n compares to stock air flow, but typically when you change an air intake, you will consume more gas.

my mileage sucks too on streets.... so i bike!

 

I get 18-20 miles per gallon and my commute is mostly highway.... if I go straight highway I may get 22-24 mpg. I havent noticed any drops since I got my mods done, the gas mileage has always sucked.

 

my stock AWD sedan with my recent tune up shows 20.0 on the navi screen. Which is roughly about 280-300 before i fill up near 1/4 tank. real numbers since i bought the car has been 18.2MPG lifetime. I can get 24 pure highway if i can stay at 60mph but i hardly ever do so 70-75 means 22 MPG roughly.

No matter what my driving style is it will even out for the week. If i smash down and go 85mph one day, sometime during the week i end up going the speed limit and etc.

the EPA listed the car at 18city -24 highway or something for AWD guys. which isn't very far off.

 

If ur complaining about the gas, just wait until something mechanical goes wrong. Like people have repeatedly said inthis forum, buying used is as cheap as a new Honda, but it's not a honda.

 

OP how are you calculating your MPG? 278 miles with how many gallons on fillup?

 

I averaged about 20 mpg when driving mostly freeway... maybe 340 miles per tank. Now that I live in town and do mostly city driving I'm getting 17-18mpg. A couple mpg isn't going to make that much difference in your wallet at the end of the year.

Say you drive 20k miles/year (probably average in Houston)
if you get 20mpg you'll use 1000 gallons
if you get 17mpg you'll use 1176 gallons

176 gallon difference over 20k miles. This will only cost you another (gas @ $3.00/gallon) $528. That's nothing over the course of a year. If you want a high mpg car get an economy car. I'll gladly pay for the gas because I know I wouldn't enjoy driving an econobox.

 

Yes, these cars are terrible at gas.

I had to modify my driving style to increase my fuel economy.

Used to get 16 city / 22 highway.

A few changes in my style and in average around 18 city and 25 highway now.

Cruise control where you can and above 65 your fuel economy drops off. I get 23mpg at 80 mph, but 25-26 at 65mph. This is pure highway long distance driving as I drive 80-100 miles distance at a time all the time. So when you put nearly 25k a year on the car, you experiment a bit. Basically only way to get 25 highway was cruise control or drive like there is an egg under my foot.

New tires, inflated to 35 psi helped a bit as well. New air filter, new plugs as well.

 

OP, "Miles per tank" is a near useless way of measuring economy.

Calculate your MPG between fuel-ups (or better yet, between several fuel-ups) and report back.

 

One thing I found in CA that lowered my mpg was the fuel. During the summer the fuel mix has more Ethanol and that made my mpg go down 1-2 miles. I usually get 18-19 combined and 22-23 on freeway.

 

Make sure your tank is filling up all the way. Run it near empty and make sure the car takes close to 20 (18-20) gallons. If it does not, your tank is not filling up all the way. I believe there was a tsb for this.

 

I get 300 consistantly...