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[Infinitehaha82]

Sorry to drag this subject up all but I am having trouble finding what I need about this topic. I recently bought a 2008 G35XS about 3 weeks ago. I would say that the first week I drove it hard but I have been driving it pretty Conservative since. However I seem to be only getting about 15-17 MPG. I dont know if how the previous owner drove the car has affected it now or what. The car only had 35,350 miles on it when I bought it and it is up to 36k now. I drive about 50/50 freeway/city. I know I had read about most people are averaging around 20-23 mpg. What am I doing wrong? Or is there anything I can do to help this? Maybe reset the ECU? Any help would be much appreciated.

[biggie]

Would definately try resetting the ECU. Then make sure air filter/intake is all good. After that has anyone looked at the spark pulgs, wires, etc?

[telcoman]

Sorry to drag this subject up all but I am having trouble finding what I need about this topic. I recently bought a 2008 G35XS about 3 weeks ago. I would say that the first week I drove it hard but I have been driving it pretty Conservative since. However I seem to be only getting about 15-17 MPG. I dont know if how the previous owner drove the car has affected it now or what. The car only had 35,350 miles on it when I bought it and it is up to 36k now. I drive about 50/50 freeway/city. I know I had read about most people are averaging around 20-23 mpg. What am I doing wrong? Or is there anything I can do to help this? Maybe reset the ECU? Any help would be much appreciated.

How are you arriving at your MPG figures?

The only accurate way is to fill your tank and set your odometer A to zero

Drive 300 miles or so and refill your tank. Divide the miles driven by the number of gallons it took to refill your tank.

On my latest fillup today I drove 317 miles and it took 12.992 gallons for a 24.40 MPG

Over the life of my G since December 31st 2005 I drove 164771 miles and used 6912.986 gallons of 87 octane regular for an average of 23.835 MPG. I did try a month of 91 and 93 octane a few years ago and saw no improvement in MPG so I went back to regular.

My MPG varies according to outside temperature, weather, and humidity. My tire pressure is 35lbs when cold.

Short trips, frequent stops and starts greatly reduce MPG. I've gotten over 28 MPG on a few occasions while on cruise control on trips from NJ to Florida.

A 5 speed AWD gets lower MPG than a 6 speed manual.

Telcoman

[Infinitehaha82]

When I usually fill up I put in about 16-18 gallons and usually get about 315-335 miles until I fill up again. I have done this about 5 times since I have owned the car. I reset my Trip A every time so I can check how many miles I am driving. I did get 350 on a tank when I went on a road trip but that was almost all highway driving. I just figured I would be able to get about 350miles to a fill up since I usually run it down as low as possible before I have to fill up again. I almost want to run it out of gas and just have AAA come give me the 3 gallons of gas to get me to the gas station and then fill all the way up from empty and run the mileage from that. But I just havent been abel to do that yet.

[joe603]

You don't need to run it out of gas...just use the trip mileage/number of gallons put in.

[Infinitehaha82]

Yeah I do that every time I fill up the tank I zero out the Trip A. I have left Trip B alone since I bought the car. From what the car says, Im averaging around 15-17 mpg. I think that is a bit low considering that I do not really get on it except when im getting onto the freeway. Plus after reading quite a bit on this forum it sounds like I should be averaging around 20mpg during my daily driving. I know that is still a bit low but I do have the AWD model.

[telcoman]

When I usually fill up I put in about 16-18 gallons and usually get about 315-335 miles until I fill up again. I have done this about 5 times since I have owned the car. I reset my Trip A every time so I can check how many miles I am driving. I did get 350 on a tank when I went on a road trip but that was almost all highway driving. I just figured I would be able to get about 350miles to a fill up since I usually run it down as low as possible before I have to fill up again. I almost want to run it out of gas and just have AAA come give me the 3 gallons of gas to get me to the gas station and then fill all the way up from empty and run the mileage from that. But I just havent been abel to do that yet.

You do realize that fuel in the tank cools the fuel pump.

Running until almost completely empty can cause the fuel pump to overheat and shorten its life.
I fill up around the 1/4 mark or just slightly below.

[Infinitehaha82]

Actually I did not think about that. but if you are filling up around the 1/4 tank mark then you probably have quite a bit more than a 1/4 tank left. from what I can tell when my G says its empty I have been able to go at least another 40 miles and it does not feel like it is close to empty. But I will be more careful about that. I just like to stretch my gas as far as I can, especially since gas prices are about $4 a gallon here in Ohio.