Spent 6 hours looking through various archives. Some things I have gleaned, please comment.

If my car is 94 model it is said to have only one o2 sensor. But I see a reference that says code 4 4 3 is for low efficiency cat. Explanations for the second o2 sensor state that it detects the exhaust gas content AAFTER the CAT - does this mean that a system with only 1 o2 sensor cannot detect CAT efficiency?

Yet my ststem has displayed 4 4 3 so this might indicate it once had or was supposed to have a second o2 sensor which has beeen removed by the garage? I cannot see it now, at any rate.

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I also found some articles by people who had removed the cat and replaced it with various options including straight pipes, a high flow cat, and some with a silencer box (make not stated). Many people could not tolerate the noise from the conversions.

Anyone with more suggestions, or am I better off to reinstate the CAT?

Keith