kennner

I get about 160 miles per tank also. I have done everything that I could think of just like most. I have also changed the airfilter and o2 sensor with 0 results. It sure sucks that once a week I am sitting at the gas pumps dropping another 40 dollars plus into the tank.

GodwinAustin

where can you buy the o2 sensors for cheap online?

MTL_4runner

One of the best places I have seen:
http://www.urdusa.com/Merchant2/merc...Category_Code=

GodwinAustin

those are great prices all the other sites I googles returned 130-140 dollar prices.


is it worth it to just buy and install one at a time? - cash is low - thinking of the front one

MTL_4runner

If you are going to replace one, I would always pick the front one first.
In my experience the rear one rarely needs replacing (certainly not nearly as often).

GodwinAustin

wait Jamie are those Denso's OEM?

runner89

to get the o2 off soak it in pb then go to sears and get oneof their Bolt Out socket kits. spray it with more pb when you get home wait 15 min spray it again and go for it. my nuts were shredded but with the pb blaster and bolt out socket the job only took 30mins. On a side note I replaced distributer cap and roter,plugs, air filter, o2, and put on a new cat back and still only get about 14mpg. I run 31's with 410's. some of these engines just seem to be dogs.

p.s. all parts straight from the dealer.

Sharpe1

I'm not sure what mileage I'm getting but I know that4Runners over here generally are pretty bad compared to just about everything else.

Henryv

I'm with you on the mileage thing. I've changed plugs, pcv valve, air filter, fuel filter, both diff fluids, tcase fluid, cleaned tb, maf, injectors and seafoamed and I'm still getting around 12 mpg in the city and maybe 17 highway. Truck runs great with no cel, just gets horrible mileage. Thinking about the o2 sensor next but I got a question on that. I just did my smog check and passed everything. Does that mean my o2 sensor is working normally?

midiwall

Yes, Gadget's selling Denso OEM O2 sensors. It really is as good of a deal as it looks like.

MTL_4runner

Yep, OEM.

theryanator

Ok well it has been four months and I have done everything short of getting the injectors cleaned.

last week I ran a can and a half of Seafoam and immediately changed the oil afterwards

I filled up today and got a whole whopping 12.5 mpg, no change Is anyone else with a similar model getting this bad of mileage...is this just normal? I have a hard time believing that it is as I see other people with similar setups getting a solid 15 and up!

I am about ready to put the for sale sign on this truck, but I have put a lot of $$ into it already so I guess I just am wanting to get it fixed and make it worth it...but unfortunately it has been a very bad experience and also a money pit....uggh...and I was so excited to get this truck back in November!

midiwall

Where are you in the world? It's possible that you're fighting the "Winter Gas" syndrom as well. I think we should be out of this crap fuel at the end of next month. My last tank netted me under 11mpg. I'm not too happy right now, I was running a consistent 17+ back in October.

Did you ever get the O2 sensor out? It really could be the source of your trouble.

TACOMANATOR

I would replace th O2 sensor since you did everything else. Also, when you turn on your forward defroster it activates your AC, this could cause a drop in milage. Running in 4 wheel drive also eats up a lot of gas. I love how they put ethanol in gas to try and clean up the air, and all it does is give everyone crappy milage. Oh well, it keeps the farmers in buisiness.

theryanator

I am in Chicago....I REALLY REALLY REALLY HOPE IT IS WINTER GAS!

the Check Engine Light is not on so could it be the 02 sensor? I have been told if the SENSOR was bad the CEL would be on. Anyone have experience contrary to this? thanks!

midiwall

Yeup, I have experience with it. (so you didn't change it out?)

The CEL will turn on for a number of things regarding the O2 sensor. Most of them deal with catastrophic failure. For example, the heater core is open; the heater core is shorted; the "low range" is too low; the "high range" is too high. But, it won't turn on if the sensor is simplying not getting a good enough sniff of air because of it being kinda' clogged. And, people have found that to happen from using SeaFoam (or any kindof "clean the engine while it's running" type treatments).

A new O2 sensor is $90 from Gadget's company (click here). You only need to replace the front one.

kj454

My Dad purchased a '95 Ford Bronco and was getting roughly 12 mpg with it. He replaced the 02 sensors and added a K&N he is now is getting around 17 mpg that's with a V8.

mt_goat

Yeah, the ECU reads the front one for air/fuel ratio adjustments, the rear one just tells if the cat is working or not.

theryanator

Thanks,

I will be checking out the O2...up to this point I have heard "dont worry about it unless the CEL is on". spoke with the dealership and they said for a 1999 4 runner sr5 there are 3 different possibilities for the right O2 sensor since they used three different manufacturers to provide the sensors for that year. Anyone know anything about this?

One thing that is strange is that this past weekend I Seafoamed, oil change, Cleaned the MAF and replaced the ai filter (it had a carquest airfilter in it that seemed like junk so I picked up an STP filter and it seems to be running better...the old one wasnt dirty, just was really heavy and seemed to be very thick.) On the high way this weekend I got 18.6 mpg! I have not driven it much on the street since, but we will see if that changes at all as well, I hope that it does...I might actually hit 100 miles before the tank hits the 1/2 mark.

Thanks for the input and if anyone knows whats up with that 02 sensor manufacturer deal, give me a shout...thanks everyone!

midiwall

Nope, that's simply not true.


Yeup, go to that link I gave above for URD's ("Gadget's company") site. The breakdown on which one you'll need is there.


Remember, we've said a couple of times in this thread that the Seafoam treatment could be causing problems if the engine was really dirty. Even if it was sparkly clean, the stuff that's in that telltale blue cloud you get after a treatment isn't something an O2 sensor is "designed" to be able to shrug off.