GeneralThomas

Plain Jane 03 Lancer ES 4G94 engine automatic. No mods other than a custom shaped cpvc, under the dash handle for adjusting the air temperature.

First I want to say "thanks" for these forums. I've trolled here often & found a lot of helpful information. Figured it was time to register and ask a question.

I searched the PO421 threads but I still have a question.

I'm throwing the PO421 "warm up catalyst efficiency below threshold bank 1" code. Replaced both 02 sensors. Car runs well, no missing, normal power. After reading here, I'm going to check for fouled plugs but I don't expect to find any problems there... replaced plugs & wires approx 18 months ago.

Assuming the front catalytic converter is bad...
Called my local shop and they said the the vehicle would not pass inspection if I replaced the exhaust manifold with one that does not have a cat. There is no emissions test here, but they would catch it on a visual.

Is is possible to just remove the catalytic material from the cat housing reinstall the manifold, and install an Oz sensor spacer on the rear sensor?

I guess there are two questions here... will the engine run correctly if I do that, and is it legal? It will pass our inspection.

Thanks!