[ZachUA]

there are 2 cats right? one right off the manifold and one a little further back under the passenger side floorboard? I'm still trying to figure out what the problem with the cat could be. AFAIK the only sensor that detects anything for the cat is the oxygen sensor. The only thing I could think of is either a missing cat or a malfunctioning oxygen sensor. If it were clogged up the car would run poorly and you'd know there's a problem other than a cel.

edit: after some research it appears that there is only 1 cat and it is attached to the manifold. A common problem resulting from this is the manifold getting too hot and cracking which causes an exhaust leak that the ecm picks up and produces a cel.

I wouldn't doubt it if that is the problem with the car I'm going to look at. It will be expensive to replace either the manifold or the wideband o2 sensor. I sure hope that's not the problem. If the manifold is cracked you would think the owner could hear the distinct exhaust leak sound coming from the engine bay!

after more research it appears I could upgrade the exhaust system to an ex style. The ex manifold does not have a cat attached directly to it, instead, the cat is underneath the car (like most cars). The problem I'm concerned with is that the cat will be too far back to get hot enough for the car to go into lean burn mode.