OpTikOl

Hey guys,

I've been getting bad gas mileage every since day 1 when i bought the car, 98 GXE 100 000 clicks, 5th zigen muffler, kyb agx, eibach combo, 17 " Mags..only main mods at this moment. Rougly 300 Kilometers per 57 Liters of gas stricktly city driving (87 oct)!!!! So divide 300 by 1.6 and youll obtain your result in miles. Shortly after the check engine light came on, drove with it for about 6 months then decided to take it to the dealer. Dealer told me it was both the O2 and knock sensor. Fine so 600$ later i'm expecting to get better gas mileage. But no, in fact i'm still getting Between 300 - 350 kilometers per tank of gas and i'm freaking out. Any ideas what could be the problem, i'm using Mobil 1 synthetic oil, K&N stock type air filter..car is being well maintained! And the gas it's costing me is outrageous!! Should i take it back to the dealer, what do you guys think the problem is. All feedback is appreciated! Thanks guys!

95maxmadman

Have you always put 87octane in?
That will cause your engine to knock.
If so, you may have always have had a good ks.
Have you checked the codes recently?

cam_honestiam

iTrader: (2)

Which O2 sensor was replaced? Have them tell you, and if it was not the front left sensor, that one would be the next go-to solution.

njmaxseltd

iTrader: (19)

How heavy are your 17" wheels? Heavy wheels plus city driving distroys gas mileage. Put the stock 16's back and see what your gas mileage does. Also you should be using 91 or higher octane fuel. As 95max pointed out, that low octane may cause ping which sets off the KS code in the first place. (I bet ya didn't need a new sensor) If you have ping, the KS pulls timing back, you lose power and you gas mileage goes down the drain.

Also consider having your intake cleaned. Not just the throttle body but the entire intake system. That makes a huge difference in performance.

OpTikOl

Thanks for the feedback guys, but is it honestly worth starting to use 91+ octane fuel already at 120 000 clicks on the car. Is cleaning the fuel injectors a possible cause of this horrible gas mileage?

kushane

This car was designed to run on 91 octane gas. As for your question about "is it honestly worth..." - Yes. In fact - getting the right grade of gas in more important in cars with a lot of miles since it helps prevent detonation (ans subsequently not retard the timing as much to compensate).

My experience has been that the Maxima runs very rich till the engine gets to operating temperature. so if you a lot of short trips with enough time for the engine cool down again - you'll get less mileage than doing repeated short trips.

Your mileage (at 325 kms per 57 liters) works out to about 13.7 MPG. If you are running 87 octane and a lot of short trips etc... this might not be too far out there.

'97 5spd

iTrader: (1)

I agree with the rest, start using 91 or higher octane gas. I used 93 in my '90 mazda mpv. Not because I liked it, but because it "improved" performance, and got me better mileage, figuring out the costs, it comes to about the same considering the improved mileage. Also, make sure your tires are properly inflated to 29psi. I prefer to make it 31 for better mileage still, but don't go too high, this will drastically woresn your traction. Hope this helps