mudpuppy

I have a 2002 Tacoma SR-5 with the 2.7 4 cyl.(about 23,000 miles). auto trans., 3" BL and 3"SL, 35" BFG's. I have installed a Downey Header and initially took off the 2nd cat. (no emissions checks in South Carolina) to try to get some performance. I also have a K&N FIPK. Not all were done at the same time, just the header and cat removal. I didn't keep original cats(2) or exhaust manifold. I, of course, got the 0420 code. It's been going off every other day after I clear code. I decided to put cat back on (dealer wanted about $900.00) for the rear cat and pipe assembly. So I opted for a Magnaflow Cat. for about $59.00. Problem is I'm still getting the 0420 code. Questions: 1. Does installing a header normally cause the code? 2. Saw a "simulated" oxygen sensor that claims to prevent code. Anyone tried this product? 3. Should I go back to stock exhaust and take my lumps? Any help appreciated!! Thanks in advance from a newbie.

1989toy4wd

Just so you know removing the cat gives no increase in performance, expecially in a 4cyl. I have a 22re and when I bought it the cat was gutted, and I replaced it with a new one, and there was no difference in power at all, just a difference in exhaust sound volume. A header installation shouldnt cause the code to be thrown on any engine, I would put stock cats back on.

Elton

welcome to yotatech ... did you unplug the sensor

mudpuppy

I'm not exactly sure what you mean, but both sensors are in place. I erad about the "simulated" sensor, and it says it goes by the second(rear) cat. Of course the first cat is gone with the header installed, and I'm wondering which sensor is causing the code. If the first sensor is causing the code, would the simulated sensor after the second cat be a waste of time?

mudpuppy

also, thanks for the welcome!

mudpuppy

I may try to find a cat, but not through the dealer. I was floored..$900.00 for the rear cat, and you can't buy just the cat, you have to get the pipe too. Know any good sites where I can find new exhaust parts? Was possibly thinking of finding a good junkyard, but haven't seen any 02's with the 4cyl.

TRDatVT

The front sensor should be an upstream O2 sensor and will not change anything due to converter removal, but the rear will. I am not sure whether the simulator will work on yours, but i have done the same to my truck and am using one on my rear sensor and no codes.

mudpuppy

Thanks for the reply, I was wanting to hear from someone who has tried the simulated sensor. Wasn't sure if it would do any good or not. Did you have the code prior to installing the sensor or did you install before getting the code? How hard was the install? Thanks again!