Gas Mileage 280 miles to a tank? wtf

[blazncypher]

SO I HAVE A 01 i30 I HAVE DONE EVERYTHING I CAN THINK OF, ALL MAJOR SERVICE DONE, K & N AIR FILTER, NEW MASS AIR SENSOR, NEW IRIDIUM SPARK PLUGS, TUNE UP ETC. I WAS GETTING ABOUT 340 TO A TANK CITY AND 450 TO A TANK ALL FREEWAY BEFORE. NOW ITS ABOUT 100 MILES LESS PER TANK. ONE DAY IT JUST CHANGED AND NO ONE, NOT THE DEALER OR TWO INFINITI SPECIALISTS CAN FIGURE IT OUT . ANY THOUGHTS HERE?????

[rxm6]

I have the same problem. It was suggested to me, and I'm still waiting for the reader to arrive, to check the ecu and see how it is handling the gas distribution. I'm not too computer savvy, but I understand mechanics. So in my mechanical thinking my first thoughts are maybe a bad coolant temp sensor or bad o2 sensor. But these cars are so computerized that I was assured that any little problem with sensors would be immediately noticed by the computer...but I'm skeptical

[irax]

could be the wrong spark plugs.

[MattB]

Lose the K&N air filter ASAP. They are known to destroy MAFs.

[blazncypher]

it was actually worse before i switched the plugs. i was told to get iridium by a nissan specialist.

[irax]

Get exactly what comes on the car from the factory and thats it. If the spark plugs are for the wrong temp range it will not perform as it should.

[Beancooker]

Dude, 340 a tank city? You are one lucky SOB. I have and am still getting about 300 per tank city. But I drive kinda fast too.

[Ryan Heo]

Don't use Bosch which is most expensive thing.I threw NGK plugs away after then replaced Bosch plugs.It is horrible... hard to start... I don't know why.Just use Nissan dealer's things.

[blazncypher]

i got the ngk plugs, i do have heavy wheels and tires 245/35/19 forged lexani wheels, they weigh like 60 pounds a piece with the wheel and tire. could that be part of the problem?

[brianw]

Oxygen sensors are critical to fuel economy, too.

Big heavy wheels and tires with a larger rolling diameter (so your odometer is reading too low) would help contribute for sure, too.

[misterkey]

That sounds about right to me. My 99 i30 gets around that exact mileage, both in city and highway driving. I have no aftermarket parts either.

[A.Tech]

Lose the K&N air filter ASAP. They are known to destroy MAFs.

Lose the K&N air filter ASAP. They are known to destroy MAFs.

They are NOT known to destroy MAFs. Dunno where u got that info from. The only part that is bad for the MAF is if you lube the filter up too much with that oil the filter uses, but you only need to do that like 1-2 times a year if that. Plus your supposed to clean out your MAF element at least once a year anyway.

[nismo1219]

yea, mang! i love my k&n filter!! i have tried several different filter types during the past. i have used "apc types" from auto zone/pepboys, injen brand filters, etc. but by far my favorite has been the k&n...FTMFW!!

[daveyboy]

My 96 I30t gets consistent 23 city/mix with 29-30 highway. Odometer at 120k. Driving habits I am sure affest mileage the most. PS best plugs so far in my 30 years of tinkering with cars are Brisk racing, easy 1-2 MPG!

Davey boy

[00MaxSE]

I got over 400 miles on my tank going to Maxus this weekend. 27.8mpg.

[Ryan Heo]

What's your secret?My 96' infiniti have 250mph per 16gal.Huh... I replaced spark plugs which is NGK, air filter, knock sensor...I have no idea.Thanks.

[stearnszilla]

Driving a combo of highway and city, I regularly get between 25.5 and 28 mpg with my '98 I30.

[maxhopper]

City driving, I average about 330 miles per 16 gallons or so. highway driving with the cruise control set, I have seen as much as 420-430 miles (16-17 gallons).

[audtatious]

You don't count as you have a different gen . Remember, you were getting a good bit better mileage than I in my 2k2 coming back from Atlanta and I have been averaging 25-27mpg @ 75-85mph. Granted, my O2 sensor was screwed up......

[TakedaT]

My 99 i30 gets about 300 miles to a full 16 gal tank. That is a combo of city and highway, but mostly city miles. I do have some heavy rims, but my rolling diameter is pretty much the same as stock.


Modified by TakedaT at 10:13 AM 6/29/2007

[shortdogg1980]

i average about 16mpg on my 01 i30t, so i know ur pain, i'm a auto and truck mechanic and i've done everything i could think of besides drive the thing off a bridge, if anyone have any ideas i would love to know also, as of now i have the joker for sale, i hate to ditch it but i gotta get something more fuel conservative.