I just picked up a 1990 Civic LX. Its all stock with a d15b2. I took it to get emissions done and its twice the legal limit. The tech said it has to be the cat causing it. When he had it on the dyno or what ever you called it. I was standing behind it and could smell that it was running rich. Ive notices the smell has gotten worse in the last two days. I ordered a new cat for it. Im starting to think its the timing tho. Cause wot it feels like its inching from 4k to 5k rpms. Its not a strong feeling. it just does not feel like a smooth build up. This mite be all in my head cause Im use to driving an LS Integra. Any idea's what could be the problem with it?

 

mine did the same thing. i changed the o2 sensor and that dropped it alot. but it ended up being a leaking o-ring on my injector and a bad valve

 

Mite change the O2 and plugs and see what that does.