Hey Sloth, man I'm needing to do this on my LX. What was involved in the swap, what size tool did you use?
Extremely easy. Just get the 02 sensors off rock auto. They sell the OE Denso ones for significantly less than everyone else. I only did the upstream ones as that's why my code indicated. Actually it just indicated upstream pass side, but it's a good idea to do both at the same time.
On my 98 these are the 02 sensors : More Information for DENSO 2344169
They're only $38 ea. Around half the price of Napa who also stocks Denso stuff.
Only other thing I got, which is not needed but makes life infinatly easier is the 02 sensor wrench. You need a 7/8" one for the 100 series upstream sensors. This is the one I bought : More Information for PERFORMANCE TOOL W84008
It's only $5 on rock auto. You just need a 3/8" drive ratchet/ breaker to use it. I used a flex head ratchet. Makes it easier to work with in tight spaces.
As far as procedure just crawl under the truck (mines lifted on 34's and im skinny which makes it easier... Locate the upstream o2 sensors. Both are located where pre-cat where the exhaust turns down adjacent to the exhaust flanges on the engine. Unclip the harness. They have a lever located on the short side of the pigtail that you depress with your thumb (on the side of the pigtail attached to the truck) while simultaneouly pulling the pigtail attached to the actual sensor. Don't worry about yanking on it since you're replacing it anyways. Then you place the 02 socket on the sensor, attach 3/8" drive ratchet or breaker and rotate counter clockwise to break it free. Mine only took about 1/4 of a turn with the socket and then I just spun it off with my fingers.
Installation is the reverse. Just make sure to use the supplied copper anti-seize on the threads prior to install.
If you have fatter arms/ hands the pass side could be difficult as you snake your arm up between a few things. Drivers side is easy access. On the pass side you could remove the pass side wheel and rubber splash guards to get easy access if you're so inclined.
Downstream sensors are similar, except they use a flange with 2 nuts that secure the sensor instead of the end of the sensor being threaded. If doing the downstream ones make sure you get the gasket that goes between the sensor flange and the exhaust pipe.
Last edited: