The oxygen sensor is replaced for free in the USA only when the vehicle reaches it's first 80 000 miles regardless of the age & number of owners as stated in the factory owner's manual in the maintenance section,some Toyota dealerships are reluctant to replace it for free if that happens contact the Toyota regional head office for your region where they will give your local dealership 48 hours to comply.
On average the oxygen sensors should be replaced every 6 years or 100 000 miles or so which ever comes first as stated in the owner's manual,warranty booklet and factory service manual.
Symptoms of a bad o2 sensor are poor gas mileage,hesistation in acceleration,worse emmissions,and in severe cases after the stat opens the engine can no longer maintain stable 750 rpm (with manual 5 spd tranny) idle and the engine begins to stall.
The 02 sensor is designed to function once the vehicle has warmed up which is about after 10 minutes where the thermostat begins to open at 190 or 195 degrees Ferenheit depending on thermostat then the vehicles ECU system enters what they call a "closed loop system" then the exhaust manifold's temperature reaches 400 degree Ferenheit (I think)that's where the sensor starts to do it's job which is usually when the thermostat first opens up then the oxygen sensor senses the ratio of air to fuel and sends a signal back to the ECU then ECU compensates by increasing or decrease the open time for the fuel injectors to pump fuel.So usually the problem of stalling shows up after about 10 minutes of driving or so.Many folks think that the o2 sensor is bad but an exhaust leak can cause excess oxygen to enter the exhaust system thereby fooling the sensor into thinking there is too much oxygen,there are other problems that could cause it to give false reading such as a vaccuum leak.
If you discover that the o2 sensor is bad and it is not under warranty then from my/others experience/research purchase an o2 sensor in the following order:
1)Toyota (NipponDenso now called Denso)
2)Denso aftermarket (Same as original but sold aftermarket)
3)NTK (oxygen sensor division of NGK)
Available at:
http://www.1sttoyotaparts.com/partscat.html (10% shipping by Fed Ex or free shipping with $100 & over speak to Roger at 1-888-271-3948
http://www.Toyotaparts4U.com
http://www.toyotaofplano.com
http://www.densoaftermarket.com
http://www.ngksparkplugs.com
Note:Toyota has an organized numbering system which dictates that the first 6 digits of their 10 digit (5 digits-5 digits)part numbers represents the part # and the remaining 4 digits dictate country of origin,color code,trim package and so on not in that order as shown in the free Toyota EPC (electronic parts catalog) download at:
http://www.yankeetoys.org/docs.htm
http://oldschool.supracentral.com/htm/epc.htm
http://www.turbosupras.com/pages/technical/epc.htm
http://www.showmesome.info/hilux/inf...load_links.htm
http://www.speedtoys.com/%7Earnout/
http://www.speedtoys.com/~gemohler/epc/
http://membres.lycos.fr/doc4toy4u/se...EPC_TOYOTA.zip
Here is a post fellow poster (Todd) who posted it on another 4-Runner/Pickup discussion site about 2 years ago:
"There is a newer version of the EPC available for download.Similar in size to the older version (254MB and 220MB zipped files)I have them on my personal FTP server (not always running), and they are also on another FTP server.
Address and login for mine:
151.203.109.45 Port 21
Login: t4x4pickup
Password: t4x4pickup
Address and login for the other (usually running 24/7):
ftp.lawvision.net
User: upload
Pass: upload
Apparently they cover 1988 and up vehicles (I haven't unzipped mine yet).
Feel free to upload and download on mine.
Enjoy!
Todd E:zoddoo@hotmail.com"
For version 1/2002 the passwords are:
Europe 02052311
General 02032511
U.S.A. 02022608
Japan 02071608
Here’s the codes for the 01/2002 disks:
Europe 02022004
General 02022212
U.S.A. 02022608
Japan 01121209
NGK has a powerfull oxygen cross reference software which cross references their different part #'s into either a single,double,triple or a quad wire o2 sensors so you may find 10 or so different part #'s for your 94 pickup and all you have to do is plug those part #'s into:
http://www.1sttoyotaparts.com/partscat.html
and see which one is cheaper I think you will find one for as low as $60.The NGK cross reference software is:
http://home.att.net/~ngksparkplugs/w...ome.html-.html
before you replace the oxygen sensor soak the 14 mm brass nuts with any of these deep penetrating oils several times for several hours:
1)PB Blaster
2)Liquid Wrench
3)Kroil Oil
4)Aero Kroil & Sili Kroil
5)Toyota Rust Penetrant or High Performance Penetrating lube
6)Rust Check
the first ones being the best,also if you decide you need new ones here is the Toyota part for the exhaust manifold (brass)nuts # 90179-10175 (14 mm socket)
Oh yeah,I bought a NTK (NGK) oxygen sensor for my 85 4-Runner and it came with a gasket and a genuine made in Japan black plastic tie wrap I don't know if the Toyota or Denso aftermarket ones come with a gasket but ask them before you buy them.
To clean the throttle body remove the air intake hose and examine the intake and throttle body for excessive carbon build up if found then buy a can of throttle body cleaner labeled "safe on oxygen sensors,TPS's and catalytic converters" do not use carb cleaner make sure your engine is fully warmed up prior to using as when the throttle body is hot it dissolves the carbon easily and quickly.The labels usually specify to park the vehicle at ground level (0 degrees,no inclination) and have the engine running but I disagree I instead park the vehicle on a hill facing down and shut the engine off and hold a rag below the lip of the throttle body and poor the stuff and use a tooth brush.
Sidney® ™
Repairs tv's,vcr's,home/car audio out of my home
E-mail:sidneybek@yahoo.com
Dartmouth,Nova Scotia
Canada
1985 Toyota 4-Runner,solid front straight axle,factory cruise control,sunroof,22R-E,W56,RN60LV-MSEK,rusted rear step/towing chrome bumper with 245 000 KM
Linear Mode
