Does anyone know of a way that I can test the pre-cat to ensure it's functioning properly BEFORE I go through the trouble of installing it? I managed to get a used exhaust manifold with a pre-cat in it and I was told it was working fine, but I don't want to be bothered putting it in only to find out I still have my CEL on because it doesn't work. Any ideas?

The only way you'll know exactly what the condition of the pre-cat is would be for you to gut it....

Otherwise, you'll have to install it and see what the O2 sensors are doing.

Steve

Hmm...ok....well considering that it's not throwing any codes for O2 sensors, would it be ok to reuse the ones that are in there now, or should I just change those too anyway?

Originally posted by wcollegenj:

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Hmm...ok....well considering that it's not throwing any codes for O2 sensors, would it be ok to reuse the ones that are in there now,..

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Yes. The only one I would consider changing (if it has more than 75k miles) would be Bank 1 (firewall side) Upper as it is the hardest to change.