I had my catalytic converter stolen off my 1998 Toyota 4Runner (4cyl. 5 speed manual) about 4 years ago. I had an exhaust shop weld on an EPA compliant converter which lasted for about a year and a half before I got a P0420 trouble code. In that time span, Colorado (state where I am registered) regulations changed and I had to put on a CARB compliant converter. A different exhaust shop put this one on and gave me a 1 year warranty, about 3 months in the P0420 code came back. The subsequent replacement also failed within a few months, and I am now on my 4th aftermarket cat. The shop said they wouldn’t warranty them anymore, and claimed the engine was burning excessive oil, but when I checked the oil level it had burned less than a quart over 4000 miles, which I believe to be normal given the age of the car. I also ran a compression test and all cylinders were above the spec. (180-190psi). Do I just keep getting unlucky with these catalytic converters, or is something else going on that needs to be fixed? The car is in great shape and runs really well when a new converter is on, so I feel like a few bad cats shouldn’t make me replace it!
Aftermarket cats generally don’t last long before they trigger a P0420 code. The only time I used an aftermarket cat, I simply kept the old, failed cat, bolted on the aftermarket long enough to pass emissions, then took it off, put on the old one for everyday use, and stored the aftermarket one for subsequent emissions tests. I felt that the effort to swap them was worth the cost savings of otherwise having to replace the aftermarket cat frequently just to renew my registration.
In your case, I find it absolutely preposterous that a 49-state cat, which was legal at the time it was installed could no longer be deemed “acceptable” due to “regulations changed” after the fact. Especially on a vehicle which was over 20 years old at the time.
I would have protested vigorously, and if my appeals were not successful, unless there were major forces tying me to the state, I would have packed up and left. Especially if I was living in a rented home, and working a fungible job, which could be obtained anywhere, likely for similar pay.
Sounds like you have been using universal catalytic converters and you are getting what you paid for…
You need to find a name brand bolt on direct fit catalytic converter that looks like this…
I always used MagnaFlow or Walker direct fit cats…
Tester
It’s pretty outrageous, but I’m stuck here for a while. I’ve heard a lot of horror stories about aftermarket cats not lasting but never understood why.
I may try this again, previously when I tried to order these there weren’t any available for my model 4Runner, so I may try again. Unfortunately when they stole my converter they cut the downstream flange off so I will have to buy a new muffler and exhaust pipe too to bolt it on to.