BOSTON4RUNNER

Hi I got this code, does not seem to be any vacuum leaks etc..

It said Bank 1 P0 420 I am thinking 02 sensor

Is it the one before or after the cat?

I have a single cat 1997 3.4 liter V 6 5 Speed 4 Runner

I have replaced them before but that was well over 100k ago, so I am thinking it is ok if one again died.

Please advise!!

Thanks!!!!

bflooks

Advising you to search, Tim. lol!

There are atleast 2 new threads about this that I was reading yesterday.

MTL_4runner

I'll give ya a head start, here's one of them:
https://www.yotatech.com/forums/f2/catalytic-converter-replacement-89187/

BOSTON4RUNNER

I have read the threads,,,,,but there seemed to be alot that pointed to different things

I replaced these little guys before, I think another has passed away

so very sad

BOSTON4RUNNER

it is likely that I dont have 100 k but have 150 K or more even on the replacement sensor, when I replaced it before, the light never came on again...for a couple years...

I also do have a new cat as of last year

The smell at the back of my truck now, to me indicates faulty 02,,,,not an egg cat smell, but rather of richness or something

I had the same symptoms before,,,I just need to remember which is bank 1??is it before the cat or after

please advise!

MTL_4runner

Both of the O2 sensors are on Bank 1......Sensor 1 is before the cat and Sensor 2 is after.
The sensor 1 is usually the one that goes bad, but this is not always the case (esp with P0420).

Elton

just replace both of them and be done with it

BOSTON4RUNNER

Last night I changed the 02

It looked beat up but who knows

Then I realized I have not changed the spark plugs in eons,,and in eons I am meaning 125-150 k.....they were among the worst I have ever seen....one was hand loose!!!! we also needed some cushioned pliers to pop the plugs off on the drivers side...

The electrodes was soooo worn, it was redonkulous! also two vacuum caps on the throttle body were missing,,,,for god knows how long, also cleaned the throttle body and air intake tubing and K and N which was black...put in a new PCV valve,,the old one had 254K on it, I figure it is about time for a new one, and for a few dollars, i figure I could justify it .it sounds and runs awesome now...

which is sad, as I havent cared for the truck lately...

I go from building my Camaro which is perfect, to neglecting my daily driver, while still helping everyone on their rig,,,always the way though mechanics, people who build, work on cars often neglect their own stuff,,guess that is because if it breaks, we can fix it....

If the code comes back I will replace the cat, but that is a year old and hope is still good,,,but may have taking a beating having all types of gross gases put through it because it hasnt been tuned in so long...

Thanks for the responses.

Tim