I just bought a 97 eclipse rs and it has a straight pipe so no converter. I was driving and the check engine light came on. I tested it with the OBD II reader and it came out to be a bad o2 sensor. I can see there is a o2 sensor sticking out of the header but is that the only o2 sensor since I dont have a converter? How much is a o2 sensor and how much is it to weld a catalytic converter on my straight pipe?

Well to start off you posted in the wrong section. Your throwing a code more than likely becuase of only having one 02 sensor. I would check with your local exhaust shop to see how much they would charge for the work. As far as a new 02 sensor just call a local parts store probably around $50 for one.

To answer things more clearly than Tux...

Yes, you have 2 O2 sensors. One in the downpipe before the cat and one in the midpipe after where the cat is supposed to be. The testpipe is probably what's causing the secondary O2 to read bad. You can either use a spark plug anti-fouler to fool the O2 into thinking that there is a cat, or replace the cat.

Erik P.
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