ccorogers

before you throw your popcorn at the screen, forgive me for not knowing if there are two or four 02 sensors on my 96 LS400. Im thinking there are 2. on in front of the CAT converter and one behind it, if im wrong please correct. the other question, i want to save the 100 dollars an hour my mechanic charges, but if im gonna be throwing wrenches across the yard please let me know, i have the common sense of motors and have changed a few motors, starters, alternators and such but the Lexus is a different monster all together. how hard is it to change both 02 sensors? and is there 2 or 4? thanks guys.

PureDrifter

iTrader: (10)

you're partially right, there is one before and one after each cat. each as in there's 2 cats. 4 sensors total.

fronts are a squeeze but not too bad with the right o2 sensor socket (go rent one, regular wrench will round it off and socket wont fit...) but the rears are more annoying as you have to pull up part of the interior carpeting to get to the harnesses.

next time pls search before posting.

ccorogers

oh ok so duh, one cat on each side of the exaust system, the carpet part dont worry me a bit, i used to detail cars and that part is easy, its the underside that worries me. after taking the splash guard off is it easy access to both sensors? im a big dude and my arms dont twist and fit just anywhere. seems like its more awkward than anything, but the check engine light is driving me nuts. i just spent 2000 dollars on motor stuff then the light came on, and i refuse to pay 4-500 dollars for a simple job. and you say the fronts meaning the underside? explain the front/rears thing please.
Ok ive been at work all night and my mind isnt best right now, i think i just pictured this. theres one below your feet on both sides that is totally replaced under the car, then under the carpet there is one one each side literally near your shoes. so two inside the cabin, two below the car??? please forgive my ignorance.

PureDrifter

iTrader: (10)

will be similar, but not exactly the same, as the tutorials on this site due to you having a 2nd gen car.
http://www.lexls.com/tutorials/EFI/

be sure you need to replace the o2 sensors though, if you have a simple cat inefficency code (p0430 or similar) then it's good to check for exhaust leaks first

ccorogers

what would you say on a difficulty stage? 1-10? 10 being a lexus mechanic only one being my kid could do it. and thanks for the info
also seems like only one would be causing the code. the code reader would surely tell left bank or right bank, cause seems like replacing all four when maybe only one is bad is kinda goofy.

PureDrifter

iTrader: (10)

dude i don't know, it's laid out in front of you. i'm a half-decent mech (by passion, not profession) and it was a pretty straightforward task...

deanshark

I wouldn't say that there's a 1-10 scale on how hard it is. But if you have changed motors in the past, as you mentioned, then changing the O2 sensors on a scale from 1-10 should be a 0. If you can twist a wrench then you can do it. The fronts will be a tight fit, as already said, but they get done by everybody so it shouldn't be a problem getting any size arms in there. I mean, they're part of the exhaust so they're right there, in plain sight. Go for it.