need some help with this one. 97 3.5 v6 138,000 i've had this vehicle for two years and love it. Was surfing the other day and found this sight as well as some factory specs that state 17/19. This made me think that maybe my getting 8-10 in town is a little off. Am woring on cleaning fuel injectors. plugs are in good shape, thinking maybe o2 sensor? Other than the milage the car seems to run fine, doesn't miss at idle or during acceleration. any ideas?

With a 1997 model, if there was an O2 sensor issue, since that is an emissions related item, your check engine light would come on. you have to understand that those specs of 17/19 are on a brand new vehicle, in a fairly controller environment. There are a few consumer right companies that are trying to push for companies to post real-world mileage stats, but nothing has come thus far. I would run some fuel system cleaner through it, like something from Outlaw or Lucas. Do you have any modifications, including different tire size?</P>

Is a 2W or 4W drive. I too have a 97 Limited Edition 2W 4Runner and in fact I am getting fantastic mileage from it - approx 20 - 22 MPG. There is gotto be something wrong if you are getting such a low mileage (even if you have a 4W drive).

The check engine light did come on two weeks ago but the milage has been bad for alot longer than that. No other mods that I am aware of. Am running 265's for tires. it is a 4 x 4 but like you say that should't have this much effect I wouldn't think.</P>

Fuel filter? That little bugger has made a lot of people's lives pretty miserable, an often overlooked little gadget.

i would worry about getting it a good tune up, and possibly a good air filter, like a K&amp;N drop in, or even an aftermarket intake system if available. my car went from 22 to 24 with my K&amp;N CAI

I had an 88 4runner 5speed v6 and when I changed the fuel filter my Kilometers dropped. I now have a 91 4runner 5speed v6 same engine type and changed fuel filter and again noticed big drop in kilometers. So few months later I bought another Fuel filter, this time spent the money to buy stock toyota fuel filter and still no change in Kilometers. When I had the truck I had about 335 KM now I get about 270km. what could it be? Anyone please have an idea why this happened and what I can do to improve fuel consumption. I haven't changed my oxygen sensor yet because engine light hasn't lit up. So i beleive the O2 sensor is okay. I have tried many times to figure out what is going on but with out any luck.

So if anyone has anyideas PLEASE! PLEASE! PLEASE! help.

Many thanks in advance for any help,
Scoolro

catayletic converter possibly? I know when they start getting plugged you lose power and mileage.

Hey sorry to hear about the gas miliage. I have heard some rumblings on the internet about a BAD O2 Sensor severly impacting your runnermiliage with our model engine.

I too have a 99'3.4 Litre V6 (same model and engine as you) ANDGet this.... I heard that the O2 sensor can go bad for a long timeWITHOUT registering a "check engine" light on your dash.

You say that your gas miliagewas badWITH OUTandNOWWITH acheck engine light? With 135K,
I'm willing to bet that its 1 ofyour 2-- "O2" sensors or both.

THE GOOD NEWS: there easy to locate under your car (1 rightbefore and 1 rightafter) your catalictic converter on your tail pipe about midlength under your car.
THE BAD NEWS: the o2 sensors are expensive at your local"Stealer" and sometimes they are well rusted to the tail pipe. FYI Upon removel, Seriouslywatch yourhands as I swear that I have almost lost a whole frickenknuckle before *ucking around trying to removea stupid o2 sensor that was rusted to the tail pipe.

you can find this OEMpart for justover $100.00 each online from areal toyota dealer who (online)sellsthe same part for much cheaper than your local toyota dealer. I believe "Mossy" toyota out of Californiais a online OEM toyota discounter.

Fyi you may wish to take your car in to have the trouble check engine light diagnosed at a trusted shop who can scan your cars ECM($30 to $100.00)and find out what the realissue is..... andthen fix the issue your self.:D

especially if it isan o2 sensor, as they arepretty easy to change out (if there not rusted to your tail pipe)

good luck and let please letus know what you find out.

Very interesting read. How easy is it to replace the fuel filter by yourself?

hey you guys with bad fuel consumption,
If you havent changed your air filter or fuel filter in a while those are the two major things that cause that. Also If you have old spark plugs the fuel is not getting burned all the way. On my 99 3.5 I just had a TPS take a ****, that will cause a check engine light and the Idle will go up, wich in turn uses more gas. The CEL wont be on all the time, but goes on and off. So you may have a bad TPS and not know it if theres no light.. If you have a loss of power with the low milage you should take a look at your CAT if its plugged you loose the majority of power and milage drops. I doubt your o2 is cusing the problem if you have no faults for it. If there are faults for it, it will tell the computer to go to like a "default" type mode and just dump in extra fuel so you dont run lean and burn **** up, but i would look at the most obvious things first before you go and drop a couple bills on a new one for noe reason. Also the higher miles you get on the truck, the less it will get. after market cold air intakes help alot. You usually see a 2-3 mpg gain.