Losing my mind over CEL

Just over 94000 miles on my 03 Tacoma 2.7. I’m losing sleep over my check engine light. Yeah I know, another CEL thread, but I can’t take it anymore. I’ve got p0446, p0442 and p0420. The two EVAP codes have been on a while, probably 6000 miles at least and I don’t know how long for p0420. I couldn’t find any hoses leaking so I take the thing in to a shop and they found a frayed hose and fix it. Suddenly I have much better performance. Kick ass. Drive it around for a day any my CEL comes on again. Immediately plug in the obd2 reader and it’s p0446. I’m assuming p0420 will come back eventually. I’ve read that those two codes are often accompanied by each other, but why??? I can’t take this anymore. Do I need a new cat at under 100k miles? Seems insane. Any direction would help here.

 

Welcome aboard new member.
New gas cap and Purge Selnoid is most common fix in that order.
Replacement of vac lines with thick wall silicone works wonders also. P0420 A/F and O2 sensors replacement most common fix.
Check for upstream exhaust leaks, manifold to 1st cat. You can do this

 

I'm also struggling with these CEL codes and am interested in replacing all the vac lines. Is there a writeup or a diagram anywhere of where they are all located, and what diameter and lengths? Thanks!

 

Purge control valve?

 

https://parts.olathetoyota.com/p0420-code-toyota
There are lots and lots of threads here like yours.
The link lists the most common issues that cause P0420. The link also explains very well how the ECU detects this condition. I find I troubleshoot these kinds of things MUCH better when I grasp the totality of what's happening as compared to what the ECU is expecting to happen.
Aside from the culprits listed in the link, we've seen exhaust leaks trigger this DTC as well. ECU expecting to see a certain amount of oxygen in the exhaust after going through the cat. If there is a leak upstream of that second or after cat sensor, it could be allowing exhaust(and thus oxygen) to escape out system before being measured by that O2 sensor, make sense? And that could make the ECU think cat convertor isn't working good enough! It says 'I'm not seeing right amount of O2, so there is an issue somewhere!' now it's on us to see what is going on to cause that condition to be detected by the ECU.
I'm not the best at explaining this stuff, so ask away

 

Thanks for the quick reply. Is it possible that p0420 was triggered because of a bad air and fuel ratio before that hose was fixed? I can tell I’m getting much better performance, especially when going up hills.

 

Yes it is plausible. Good thinking.

 

with the p0420 usually means replace the O2 sensor and the A/F sensor(if equipped)

 

I did all my lines with this kit:
http://www.siliconeintakes.com/liquid-air-adapter/silicone-boost-vacuum-hose-p-590.html

Still got some leftover too.

 

I guess the annoying part is that the p0446 just came back on and I’m assuming that the p0420 will accompany it. Also there’s this:

 

If a rich fuel mix condition was run for an excessive amount of time, months or years, it will kill the cat convertor prematurely. Unburnt fuel mix is number one killer of the cat

 

Does exhaust leak out of there? Looks like it might. If so, I'd prolly fix it. Could be part of the problem creating that condition.

 

I had all those same codes on my 3.4l v6 I replaced the 02 sensor along with the A/F sensor and after a few drive cycles the CELs stopped, thank god

 

http://www.siliconeintakes.com/liquid-air-adapter/silicone-boost-vacuum-hose-p-590.html