Hi, I've owned my 2003 G35 coupe for about 2 months now and I'm wondering if I should get it checked out. The car runs great but I'm getting an average of 13mpg. My wife drives the car everyday day to school, which is a 10 minute drive. I know the short runs are not the greatest for fuel economy, but I was still expecting a lot better, especially since it's so much lower than what Infiniti claims it should get. I’m not expecting great fuel economy from this car but I’m wondering if there is maybe a problem that’s more serious and the poor fuel economy is an indication of the problem. The car is not driven hard and I just recently had an oil change and put in a new air filter, I was going to have the fuel filter changed but the guys at the oil change place didn’t know where the filter was, so I guess I’ll have to have it done at the dealership. If anyone has some advice it would be appreciated.

 

Reset your ECU. You will see a good results just from this. There is a HOW TO in the DIY forum.

 

or the simple 1..un plug the battery over night and let the ECU
relearn again

how many miles? plugs maybe fouled

 

You need one of these...



.

On a serious note, a tune will not solve any of your problems.

Like they said, you can try resetting the ECU; see it that helps.



.

 

Thanks for the advice, I will try resetting the ECU. The car has 45,000 km's (28,000 miles) on it, so the plugs should still be good, but you never know.

 

Ouch that sucks. I just got 23mpg+ on my last tank. 23.426 to be exact. I always write down my miles on my Gas receipts. Even my worst was above 18mpg.

Something is terribly wrong there. I hope you and your wife are putting in the correct gas.

 

We're putting in the right gas, I know that’s not the problem. I do the same thing as you, I write down the miles on the receipts, the best I ever got was 16 mpg, and that was mostly highway miles.
I reset my ECU, but I guess I wont know if it worked until after a few days.
The crazy thing is I had a 1997 Formula Firebird with a 350 in it before this car and it got about 18-20 mpg, I was really shocked when I started getting worse gas mileage from a car with less power and a smaller motor.

 

Keep us updated man..

hopefully reseting the ECU fixed your problems!

lets hope!

 

23?! you drive thing like a girl or what?!

 

Hmm...what about cleaning your MAF sensor?

 

well if the ride was parked for some time? your plugs could
be fouled..pull 1 out from both sides and take a look see

 

Get a reputable shop to do a proper fuel system service including MAF and TB cleaning; our VQ's don't need tuning till we pass 100K and there is actually nothing to "tune" except changing of the plugs and the service I just described...

Also, It is stupid to re-flash etc. without doing the complete fuel system service, but both would be a huge improvement.

 

I reset the ECU and that did nothing, so yesterday I replaced the spark plugs. The first plug I took out, I think it's cylinder 2, looked like it had oil on it, all the other plugs seemed to be dry though. I'm going to run the car for a couple days and pull the plug again and see what it looks like, hopefully I don't have a problem, but if I do the car still has warranty. What do guys think? Thanks.

 

As much as I hate to say this these cars are really bad when it comes to fuel economy. I work 10 minutes away ( city driving ) and if I'm lucky I get 225-250 per tank. Now on the expressway I get up to 350 miles per tank running it. So go figure. I would recommend taking it to the dealer and have it checked out.

 

Do it yourself, very simple stuff. Go to your auto parts store and get MAF and TB cleaner, take off your intake tube and spray them down. Put in a fuel additive like Chevron with techron in the bottle or Redline and fill up your tank. Reset your battery over night... your plugs are fine with 28k miles.