2001 V6 automatic catalytic converter

I have a 2001 Tacoma V6 with the off road package. The check engine light went on so I took it to the shop. They diagnosed it with DTC P0300-Random/multiple misfire, P0303-cylinder 3 misfire and P420-Catalytic converter Bank 1. So they replaced intake gaskets, spark plug tube seal and plugs. Told me the catalytic converter had to be replaced due to age. So I got the catalytic converter replaced at muffler shop. Then the light came on again. Took it back to the shop. They then diagnosed it with cylinder head cracked. They then replaced both heads. Took it home and within 300 miles the light came on again. Took it in again they diagnosed cycling duty for air fuel sensor and injectors duty cycle the short trim and long trim had no charge, with the injector valve should have P0420 Catalyst system efficiency below threshold Bank 1 replaced air fuel sensor and oxygen sensor and PCV valve. Told me it is throwing code now because the muffler shop put the wrong catalytic converter on. HELP!

 

Not sure how to help… there are numbers on the catalytic convertor that are used to determine if the convertor is a California compliance convertor or a “49 State” convertor, either way, a new convertor should not be throwing a P420 code. If there are exhaust leaks that could give a false P0420 code.
When the truck had the misfire was the check engine light flashing while you were driving and if so, how long did you drive it that way?

 

If the shop put the wrong CC on, they should make it right for no charge...

 

On July 5th the light came on and stayed on. I couldn’t get it into the shop till July 10th to check it out. We didn’t drive it except to the shop 5 miles away once the light came on. At 194,020 they did the first work on the plugs. then on July 13th I had the muffler shop put on the catalytic converters.
On July 12th the light came on again, so I had the shop work started on July 17th and got out of the shop on August 11th. At 194,162 they put in new heads.
Then on August 23rd the light came on again and got it into the shop on August 28, finally got it out of the shop on September 9th. At 194,504 they did the sensors and told me I had the wrong catalytic converters on.
Each time the light came on we drove it home and back to the shop.
I’m going to check with the muffler shop and see what brand and part numbers he put in.

 

Crawl underneath, assuming you're in CA, the cat should be stamped/engraved with a CARB EO#

Take a picture of the EO# and your emission sticker from the under side of your hood. That sticker will contain your emission family number.

I can help confirm if the cat you bought is the correct one for your tacoma if you can provide that information.

Almost seem like the repair shop is pointing the finger elsewhere to get you to leave and not go back.

 

I kinda agree- sounds like they went with the parts cannon and don't have actual answers. You'd need to have a damn good reason to replace the heads...

@OP- I would suggest finding another shop for a second opinion. Try one of the regional sub forums on this site to find another reputable shop in your area.

 

Talked with the muffler guy today and he put on AP converters. #641188 and 642181. Did he put on the correct one? My tag under the hood says
Test Group 1TYXT03.4FFP
EVAP FAMILY. 1TYXE0095AE0

 

First question will be, are you a CA resident? If you are, the shop shouldn't be able to purchase non-CARB cat, which make it illegal to buy and resell as a business. With that being said, I doubt you're a CA resident.

Plus, I don't think AP exhaust make CA legal CARB compliant cat because they didn't fork $$ for a CARB EO# (unless they recently went CARB compliant, they're known for Federal emission). With that being said, 641188 is the correct front cat and 642181 is the correct rear cat for your year tacoma, if you're not a CA resident.

AP Exhaust #641188 & 642181 notes: "Not for sale or use on vehicles licensed in the states of CA, CO, ME and NY. Restrictions may apply in other states. Check with your state authority for details. Federal and California emissions. Not for sale or use on vehicles licensed in the state of California and New York (New York vehicles with California Emissions). Check with your state authority for details."

 

Anyone try a new downstream O2 sensor? It's throwing the code with 2 cats...
AFAIK there isn't a higher electronic standard for CARB trucks, it's either good enough for the ECU or it's not.

 

Yep and I think OP mentioned both sensor were changed.

 

If you're a CA resident with test group 1TYXT03.4FFP:
Front: MagnaFlow #447185 with CARB EO#D-193-103
Rear: Magnaflow #447219 with CARB EO#D-193-103

If your MIL light is on, visit your local O'Reilly/AutoZone, they should have code scanner and be able to tell you what the code is. Should be P#### and let us know what is it. Sometime, shops are dishonest and if they're caught in their greed, they'll point fingers elsewhere to confuse the customer so they'll be off the hook. I wouldn't take the bait and go elsewhere, especially with all that work done. Visit your local auto parts store, pull the code, and let us know. If the code is truly a P0420, crawl underneath and feel/listen for an exhaust leak while truck is on. Be extra careful as the exhaust system will be HOT.

 

I took it to O’Riely’s last night and it got a P0420 catalyst system below efficiency 01. The dealer is telling me it has to be the Cali one regardless if I live in California or not? Trust isn’t there with the dealer anymore

 

I would call that nonsense, lol. I personally know CA owners eliminating the front cat and running just the rear cat without a code or running the front cat with a straight pipe for the rear cat without issue.

Make sure there's no leak

 

What I would look for is an exhaust leak. That will more than likely be the issue imo especially around the flange. The top flange, above the front cat, is notorious for rusting and breaking studs when unbolting. If its not tighten or missing a stud/but, it will leak, make sure there's no leak there. You should be able to somewhat hear the leak and feel exhaust leak at the flange by putting you hand there but be careful as it is HOT. I would do the same thing for the flange between the front and rear cat, because if there's a leak between that, it can trigger the code. Typically imo, any leak after the rear cat will not trigger the code.

 

I’m thinking that they did the first repair job and didn’t look deep enough for the cause of the misfires on 3. When they told me the cats needed to be replaced, I replaced them. The next time they discovered the cracked head. Since that was after the new cats were installed the leak caused the new cats to go out as well as the oxygen sensor and fuel sensor? Any thoughts? I’m thinking they are responsible for new cats and new sensors.

 

It would take cats a few thousand miles to burn out from misfires. So trying to pin the shop down for the cats and sensors wouldn't be a great approach.

Like I said, I would try to find another reputable shop and get a professional opinion rather than an internet opinion.