Yea, you're running lean and need a tune.

 

but when your runing lean doesnt engine light comes on correct me if am wrong? thanks

 

[QUOTE 95% of my driving is turnpike. I drive primarily two extension which are are approx. 220 mi. round trip. over 3 years of driving (14000 mi) the mileage is always 27.2 mpg) which I think is great...BUT gasoline is going to continue to go up because of Quantitative easing 1,2 and now 3 which devalues the dollar...I plan to buy oversize rear tires as soon as the chity dunlaps wear out.. I am going up one size to 255.45-18. these tires are l/2" taller and will raise the back of car l/4"..They will also decrease numerically rear axle ratio. for folks that do no mind a minimally reduced 0-60 this will increase your MPG by 2%. so in my case I would be looking at 27.7 and a much nicer softer ride with the MICHELIN'S.

 

If it exceeds thresholds sure, if you don't then no. Its like the PSI in your tires, the sensors wont come on for 2-3 PSI missing, but 6+ and its there lol

 

Wrong. That would point towards running rich.

 

550 kilometers to the tank full, u do the math. I care less about the cost of gas. I own a 25' boat, 350 carb. and it sucks gas.................but I do not care.........its all about the experience!

 

These threads are all over the place on g35 forums. I tend to blame the driver/owner. Unless the person complaining is relying on the Navigation's mileage gidget, or is just bad at math, then there is clearly something faulty going on.

About 3 months ago I did about a 14 gallon "test" and achieved 24mpg for about 50/50 Hwy/city driving. This was on a 2005 6mt coupe in CA, using 91 octane, utilizing the A/C constantly (drawing electric), usually 90 degrees outside during the day (most of my driving time), drawing 400 wrms from an Amplifier occasionally, and occasionally multiple people in the car (extra weight). My G, at this point of 24mpg, had a Kinetix plenum, k&n drop-in filter, z-tube, Stillen CBE, and Osiris e-tune (useless...as I later saw the effects of an e-tune vs dynotune, on my powerband and AFR). I generally cruised at 80mph on the freeway and accelerated through the gears shifting into 2nd @ 15mph, 3rd @ 20mph, 4th @ 30mph, 5th @ 35mph, 6th @ 40mph, using a feathering gas pedal (not always, but as a general guideline).

I now have a turbo kit which made 340rwhp and 340rwtq when dyno'd last on a dynometer 224. All other parts mentioned above remain. My driving style remains the same (usually, with occasional spurts of acceleration). Here's my latest fill up: 407miles and a 16.9 gallon fill up = 24.1 mpg





Btw, I checked my speedometer versus a GPS speedometer. Almost dead on.

 

+1 jninja26 is correct

 

mpg varies depending on location, spark plugs, tire psi, air filter.

I averaged 29.5mpg highway driving going from norcal to socal in 103 degree weather with the ac on full blast. combined i usually average 22-24mpg. All city i usually get around 19mpg.

I shift at 3k at 20% throttle for each gear with occasional redline acceleration on freeway on ramps.

i'm stock except for Kinetix HFC, K & N air filter and suspension mods.

 

This

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