Rep Power: 0

Alright, SO to start off, I just bought a 1997 honda civic CX. The odometer said 137k when I bought it. Everything seemed in order and it ran, so I bought it. I didn't carfax till a couple days after. Found out the odometer was rolled back. Anyway, my primary problem is I have a check engine light because of the o2 sensor. They put aftermarket headers on the car and I need to kno what to do to make the car passable. I kno there's one 02 sensor connected right where the headers start, but where's the other two? Also, with the cars chassis having possibly 275k-300k miles, should i even keep it as a project car or buy a new civic and transfer everything over? If I should just keep it, what would be the first thing I would need to fix? Thanks

 
Rep Power: 242

What was the code?

There's a sensor before the cat (The one you seen in the headers) and one after the cat.

 
Rep Power: 517

Post the code first, let's see what you have.

I think it should have a cat setup like this


Is this setup still in place?



Someone could have simply had a bad speedometer and replaced it. Is there any official mileage change sticker in the drivers door jamb?