Willing to give it a shot but can't find any at part stores websites that fit my 08 4.7 4runner.

You don’t buy them by vehicle model. There is a specific part number that you can get right at any Autozone, or Advance Auto in the Help section. I’ll see if I can find the thread with the part number and instructions. Basically you have to drill one out to 1/2”, and the other at 3/8” and screw them together, then screw the sensor into them.

Here is the thread that has the part number and instructions
http://www.toyota-4runner.org/proble...converter.html

worked for me. having just below a 'high efficiency cat' is no issue with no less than 4 cats! plus a back box. i will replace exhaust parts with parts with cats when they fall apart, until that time .....

Been wrestling with this code for a while now, when I clear it, it comes back after 350-400 miles. Considered replacing the downstream O2 sensor, but the anti-foulers seem like the reliable 'fix' for this code being thrown out intermittently so I'll give it a whirl.

Thank you Terminator03, I'll give that a try to fix VCS TRAC/TRAC OFF light. I've done everything else..ha!

By the way, the Spark plug Fauler fix, although it sounds like a good one, will not work for California smog test. The test guy checked visually for it and also ensured that my new cat was legal for Cali.

Well, nearly a year and about 6000 miles since my last post and the CEL frequency has really increased. I'm to the point in the last month or so where it comes on almost every time I drive the truck.

I actually just had it into my exhaust shop to get my rusty tailpipe replaced today. I had hoped that might help the issue, but I've popped it 3 times in my travels today post-exhaust work.

He didn't find any other leaks but I haven't done the blower test on it yet (we are deep into sub-zero winter here)

I think I just may go with the defouler (though I'm sure it's all rusted to heck under there) and see if that works. We have yearly inspections here but it's safety related, they do plug in the OBDII reader and make sure there are no codes though. I doubt anyone would notice a defouler.

I'm experiencing no power or MPG loss.

I'm using a wifi code reader and an app on my phone to read and clear the code. I suspect it is worth doing a full decharge by undoing the battery for a while to truly, deeply, reset everything.

Adding an update to this after 1 year and 25,000 km later, the P0420 and P0430 codes have come back intermittently in the last few weeks.

Had the truck up on my buddy's hoist tonight and found a very tiny hairline crack at the y-pipe, bottom side. Marked in red in pic below.
You literally wouldn't notice it without a magnifying glass or running an exhaust leak test. Simple weld job fixed it right up.
I was somewhat surprised that tiny leak even that far from the downstream O2 can suck enough oxygen into the system to throw these codes.

Attached Images

 

Had the CEL for the P0430 again, I unplugged the O2 sensor, cleaned the plug, put some dielectric grease on, and hopefully it will stay off that way.

Anyone tried this product for the P0430 code? Amazon.com: EVIL ENERGY M18 x 1.5 O2 Oxygen Sensor Restrictor Fitting Adjustable Gas Flow Inserts Cel Fix Bung: Automotive

I installed it using the middle adapter but the code came back within a week. Do I now move to the more restrictive/closed adpater, or do I go to the more open ring?

I have been going through the process of trying to figure out why my CEL kept coming on after trying a lot of the suggestions on this thread and getting various results. The one constant is that I always get the p0430 code. I had times when CEL would come on 5 miles after reset and as many as 225 miles before coming on. The most expensive thing I did was change all 4 O2 sensors. I have a 2005 4Runner with the 4.0 v6 and it runs strong with no real hint of cat problems. In researching I saw where a Toyota mechanic said to just run premium gas for a couple of weeks and thought why not? I filled up with 93 octane but mixed it with about half a tank of the lower octane that was already in vehicle and added a bottle of STP octane booster. Got to about a quarter tank and filled up with 93 and added Lucas octane booster. Drove about 50 miles and parked. Got in this morning drove about 5 miles and CEL was on. About an hour later got in to run to town and the CEL and VSC Trac lights were both off. Drove around, stopped and started vehicle multiple times and lights never came on again. I have never had the lights go off on their own, always had to reset.. I am crossing my fingers because all the crap that I have done to no avail is crazy if the fix was this simple. I will run this tank down and see what happens when I go back to regular gas. May come down to just having to add a $7.00 bottle of Lucas octane booster every other tank to keep the annoying lights out. Although even with lights on I never saw any kind of performance decline...

I doubt your fix will work. The cats are bad. Either you get new cats, some spacers or I can make you these mini cat caps that will fix it:

Say Hello to my Lil Friend

Little known fact; the spacers cause a loss of about 1mpg vs. my mini-cats. I have proved that the signal is erratic with spacers in Techstream and the total engine efficiency is lower than with a solution like my cat caps.

Duffdog, do you have pictures of your mini-cats that you make?

I had the code on my lexus is300 with 250,000 miles. After spending $400+ In parts to replace all 4 O2 sensors and the code returned, I installed the anti-fouling adapters and the code never came back. Who gives a rats butt about 1mpg loss if the offset is $1500 to replace the cats? 10,000 miles/year ave at $2.20/gal = $71 loss in mpg. (18mpg vs 17mpg)

The spacers were $12 for a pair. You drill out one so the sensor can fit, then screw that one into the second spacer and install it on the exhaust. Super easy and it works. Whats odd was only bank 1 needed it. ��

I have a 07 limited with a v8. I have over 254000 miles on it and no major problems. I have the secondary air pump problem and will take care of that with a kit from sly fox. I also have a hole in the cat that you can see when I dropped the pipes but was code free for a very long time. Think I will try the shop vac to test for leaks, I also got the freeze frame numbers. Shortf bank1 ,.8. Longft 1 was -.8. Shortft 2 3.9 and longft 2 was -.8. O2B1S2 (v) .175. O2B3S2. .195. O2B1S1. 3.106 (v). O2B3S1. 3.377(v). EQ RAT11. .986. EQ RAT 31. 1.042. O2S 31(ma). .047. Cat temps were1400 pre cat and 1000 post cat. So with numbers like this it showed that bank 2 has some minor differences. Could a pre cat leak cause this. Thanks to the forum for any help I get.

A physical hole in the converter? Yeah - that will trip a code.