I just bought my first actual car-98 Integra GS-R. I thought i got it pretty cheap at $6000 at 89000 miles, but I'm finding quite a few annoying problems. My main concern at this point is that it runs extemely rich. I got about 16 mpg on my first tank of gas. When I accelerate hard, I can smell unburnt fuel inside. I had a friend stand behind while i revved it up to about 7000 rpms, and black smoke poured out of the exhaust. I checked the spark plugs and found that they were in terrible condition. I bought new NGK's and replaced those, but to no avail. Also, my air filter is pretty dirty so i took it off in my dad's shop and ran the rpm's up again, but it still kicked out black smoke. My check engine light came on with three codes. I made a terrible move (before I had gone discoverd how rich it was running) and cleared them to see if they were erroneus and they have not returned but my gas mileage is still bad. I recall the codes to be emission control problems and one to be igniton/misfire. The car does not knock, or at least noticeably. Is this all because of an O2 sensor? What are your solutions? I'm stressing out here.

 

Either your timing is way off or you need a valve job if you're getting that kind of mileage. I would get your dad to pull the head and see what he finds. Also change your oil. You might have to switch to 10w-30

 

Update-I no longer have a misfire code. Also, my dad has no involvement in this project. It's all me. Sorry but that's kind of a pride thing.

 

Replace the o2 censor then go from there.