REPAIR DETAILS

Been a good car for wife with low miles. Last year, car misfired badly. I had the ECM rebuilt. I had a mechanic install new motocraft plugs and a fresh six pack coil set. Car ran perfect for six months and about 4000miles. However, after that repair, I had a chk engine light come on with the PO420 and PO430 codes that I never addressed. So a few months ago, car began losing power and had it towed home. Its starts fine everytime but within a minute it idles super rough with an awful poisonous smell. SO..I think the O2 sensors are bad, or the catalytic converter is bad or both. I have TWO NEW O2 sensors I bought awhile back. Car is in garage and can bee worked on in there if needed. May need other parts.