Hey guys... So I drive an AT 2005 G35 Coupe..... I'm getting an average about... 160-180/Full Tank.......
What kind of problem am I looking at?

 

Depending on mileage you may want to start with a new air filter and spark plugs. If you're using cheap oil, step up to a quality synthetic. If you change anything, you may want to do the ECU reset procedure as well. None of those serve to directly affect your gas mileage, but it's an additive effect of keeping your cars maintenance on track that will yield better performance all around. Other than that, just keep an eye on your driving habits.

There are some gas mileage variances with these cars, I don't think anybody really got the bottom of why. I get about 20mpg if I'm lucky, some people here get 15mpg and yet others get 25mpg driving mostly city. Go figure....

 

Dude, your gauge might be off. 160 - 180 miles per tank!! you will go broke before you get to where you are going i get at least 300 miles per tank and i act a fool sometimes.

 

When you fill up, how much is a full tank?

A lot of G's (mine included) have this issue with the fuel tank where we can't fill it up all the way. I can only fit about 13 gallons in mine, but I have an appointment with the dealer to get it fixed under extended warrantee next Friday.

If you're filling up 20 then something is definitely wrong, far beyond the use of any synthetic oil. Try an ECU reset (unplug the negative battery terminal and pump the brakes to discharge any residual energy in the ECU) because your ECU controls a lot having to do with your fuel delivery.

If you're still getting it I would highly recommend getting it to a reliable shop so they can see if there's a sensor failing.

 

i get 16mph it says.

 

Very good advice....^....check your tire pressure run nothing less than 35 PSI. About every second oil change add a bottle of Red Line Injector cleaner to your fuel tank. All these little things should get you at least decent mileage....Oh and you don't need to leave the stop light first.
Gary

 

Blasphemy!

160-180 mpg is pretty sorry.

Hopefully you can figure out your problem...I would start with the Air Filter because on my old explorer that was the problem it was doing the same thing...bad bad Mileage

 

my goodness... im gettin 160 on HALF A TANK and i dont baby mine that often (i just got her so i need to break her in) LOL
but in all seriousness... how many miles? whens the last time you had any maintenance done?

 

damn, the only time my car eats gas is if i havent changed the oil for awhile. but ive gotten 370miles outta full tank. mostly hwy

 

370...DAMN! did you swap out the motor and replace it with a 4 banger or something? LOL
thats impressive!

 

My car has about 52,000 miles on it. I Just recently got a Mobil 1 Synthetic oil change.... Only mod I have is a Cold-air AEM Intake.... but even before that mileage was terrible... I get it checked quite often because its my baby... I bought warranty on it so I guess I will go get my car checked at the dealership.... hopefully they wont bitch at me for the intake loll.

 

How many gallons do you put in when you fill it up? That should be more important that just "filling it up"

 

Suggest following TCAT's advice, in addition clean out the throttle body. After disconnecting the electrical lead, a re-learn of the throttle body should be conducted. Just don't drop it. No reason for the poor mileage. 2004gx will 162K and get 400mi to the tank, I also find that I get better mileage from 89 octane than 93 octane.

 

my gas gauge is off as well. The good time to get gas light comes on when i have any where from 10-7 gallons left in the tank when it should come on when there is only 4 gallons left. So when the light comes on i know im only at like 200mi but i dont fill up till like 330ish and still have 3 gallons left in the tank. and FYI the G holds 20 gallons

 

I get about 210 miles per tank on mine. I drive pretty hard and its all city. I thought that was low.