I Just Bought A '98 Maxima Se Auto Fully Loaded And For Some Reason It Is Eating Up Too Much Gas. From A Full Tank (18.5 Gallons) It Is Giving Me No More Than 200 Miles. Half Of The Time I Have The Ac On At Low Fan, Never Usually Go Over 3000 Rpm. Half The Time Im In The City Streets And The Other Half On The Highways. The Specs Of A '98 Maxima Has 21-22 Mpg For City And 27-28 Mpg For Highways, Which Would Mean My Mileage Should Range Anywhere From 388 Miles Per Tank To 518. So Why Is It So Low? So Far I Just Did A Tune-up With Spark Plugs, Fuel Filter, Air Filter, Oil Filter, And Oil Change. And It Is Still Barely Getting 200. Do You Guys Have That Too? Is There Something I Can Change In My Car To Get More Mileage? Please Help.

 

check tire pressure and see if you have any hidden codes in your ecu.

 

i get about 300-330 per full gallon...
since u did that tune-up
i would say check for leaks...if there is any

 

No Leaks, So You Are Saying It Is Probably The Sensors Right?

 

Oxygen sensors and Knock sensors can cause bad gas mileage.....

 

Check your knock sensor, check for any code related to that.

 

How Can Tire Pressure Cause Bad Gas Mileage?

 

tires with little air won't roll as easy as tires with the right amount of air...

 

You live in NYC get used to the bad gas mileage due to the stop and go traffic jams of NY.

I get around the same maybe a little higher.

 

But More Than Half The Time Im On The Expressways.

 

Read the STICKIES. A section is titled. "Why am I getting such bad gas mileage"

 

Stop typing in caps.
Start reading stickies.
You are supposed to read and know the stickies before you start asking questions.

 

BTW dont post in the stickies, you'll get banned

 

My shift key cringed when it saw this thread.

 

DAMN THAT'S SOME MILEAGE SON!

 

i get about 400mi/tank, 23mpg.

i think u have a ghost knock sensor problem...u should check the sticky and read up all the information regarding knock sensor....

 

Try a different gas station.

 

wtf? if u have nothing helpful that contributes to this thread, don't post.

 

3000 RPM seems to much to me. Since I am a fuel economy wacko (kinda poor to pay for the gas) I always keep it under 1500 unless while accelerating unless I go into the last gear, when it revs more.

 

Well, that worked for me. I used to go to a Holiday gas station because they had 93oct, then went to a Shell that only has 92 and mileage improved a lot since. I thought he should consider a different gas station.

 

yea that`s what i do as well, try not to go over 1500rpm, do no more than 65 mph on the highway and close your windows (it does make a difference in the long run, i`ve done some test before with the two front windows open on the freeway, i get about 10 to 20 miles LESS out of the whole tank).

theres a few more thing your can do to save gas, IE. try not to let your tranny downshift unless it is neesesry;let go of the gas if you see a yellow/red light is coming up, or even hit the brake slightly and wait for the next greed light to avoid coming to a complete stop.

i got 400ish mi from the last tank 15 gal when i fill up, that`s 26mpg.

 

I just realized this is a gas thread and that means

 

if i had a knock sensor or oxygen sensor problem, wouldn't my check engine light come up?

 

Not always, it is very common that a ks will not light up the engine light.

 

i believe KS never trips the CEL. O2 sensors will though. 2 front O2 sensors and knock sensor are dead on my car

 

Is it true that when you get a CEL your timings are retarded enough to cause bad gas mileage, especially with several mods? (ie y and test pipe)

 

eh.. i'm getting 22-24 mpg on the highway mainly. Its not too bad. 300+ per tank, i normally fill up when i hit 1/4 tank. And i haven't done any tuneups or anything. I just drive the thing. mainly with sunroof open at about 75mph.

 

Its not COMMON its a FACT

 

I was wondering how long I would read before someone caught that...

 

holy capital misuse batman!

 

fuel filter + PCV Valve= 7-9mpg better then b4, at least for me it did. my car was getting horrible mileage so i did new synethetic oil, pcv valve, and new fuel filter and now im getting awesome mileage. about 25mpg city and 30 highway

 

Anyone who drives a Maxima like this should be b!tch slapped. Keeping your engine under 1,500 rpm is seriously lugging it and you run the risk of carbon locking your engine. Get on it, son, or buy yourself an Echo, Prius, Geo Metro or some other POS!

 

Bobo's right. Prolonging acceleration that long is abuse to your car, your pride, your friends' pride, and the poor SOB behind you. 3000 RPM is safe.

 

i have the same problem i gt horrible gas milage. i think well i know one of my oxygen sensors is bad and i dont have a catylitic converter just a pipe and i also got a full catrback and y-pipe? repleaced my kcock sensor and my pvc vavle and my fuel and oil filter not to long ago so i dont think its those i need to get a new oxygen sensor and a catylitic converter that will prob help?