So we bought a used civic ex (1999) v-tec from a used lot and got a pretty good deal on it. The only problem is that the day after we bought it the engine light came on. We replaced the Knock sensor and we passed inspection, however the same night the engine light came on again. Anyone have any idea what the problem could be?

 

ohh, and could the air intake that came with the car be setting it off?

 

you need to check on what CEL is coming on.