P0420 - tried everything!

2000 TOYOTA CAMRY
193,000 MILES • 2.2L • 4 CYL • 2WD • AUTOMATIC
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AMALTHEA
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P0420 was on, cats were replaced with Bosal California approved cats as well as new Denso sensors. Readiness set, no codes for several thousand miles.

Code has returned, no other codes.

Things I have tried:

Fuel pressure does not drop when vehicle turned off
Replaced leaking intake tube
Replaced broken upper resonator box
Replaced exhaust resonator and muffler (due to leaks)
Replaced EGR intake gasket (smoke was leaking out while smoke testing)

LTFT remains above 15%, although before the above items found leaking during smoke test, it was above 18%

I am unable to find anything else leaking during smoke test. I do not know where to go next.
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Mar 22, 2017 at 1:01 PM
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WRENCHTECH
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Just because California accepts the replacement parts does not mean they meet Toyota standards. There are many vehicles that have tolerances set so tight that aftermarket products will just not work. I suggest using an OEM Cat.
Mar 22, 2017 at 4:15 PM
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AMALTHEA
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I'd like to explore all avenues (as it may have been misdiagnosed to begin with) before I condemn a second cat. It appears they're working and doing their jobs on these o2 graphs.

Does anyone have thoughts or advice on this high fuel trim? Are there places to check that may not have shown up on the smoke test? Anything I can smoke individually?

I'm not finding a test or specs on the MAP sensor, does anyone have this information?

I have done some testing, if anyone needs more information to help, I may have it
Mar 22, 2017 at 4:25 PM
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WRENCHTECH
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About the only other thing that will set that code is an exhaust leak ahead of the catalytic converter. The specs to set that code are very tight. The rear 0/2 has to mirror the front 0/2 for an extended period of time which is pretty difficult for anything else to trigger.
Mar 22, 2017 at 4:56 PM
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AMALTHEA
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I cannot hear any exhaust leaks or see them. Can I smoke the exhaust? Maybe go through the O2 ports?
Mar 22, 2017 at 5:10 PM
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WRENCHTECH
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Yes you can. Most smoke machines come with a tailpipe cone adapter, although coming in ahead of the catalytic converter would be better.
Mar 22, 2017 at 5:13 PM