I'll try to make this as short as possible for a long story. I have a '92 Paseo 1.5 5 speed. Around 200,000 miles started running rough, dead cylinder, turned out to be a total of 3 burnt exhaust valves. I replaced the burnt valves, hand lapped the rest, put new valve stem seals in, changed the oil. While I had the head off, I poured some of the Seafoam cleaner on top of the pistons as I have heard that the rings can get a lot of carbon built up on them. Car ran awesome but at the end of the 3rd day when I exited off the interstate the oil light flickered on. In 3 days it went through 3 quarts of oil. Only thing I came up with was I had used a hammer on top of the 11mm socket and lightly tapped the seals down instead of just pushing them into place by hand. So I tore it back down put in another new set of seals by hand only. Fired it back up sounds great still. But I noticed a lot of black smoke when I gave it gas. I checked the oxygen sensor and it was reading like it was fixed at zero ( 0 ). Easy enough fix, so I decided to take it to work and would pick up the sensor on my way home and replace it. It had a lot of black smoke, couldnt tell if there was blue though. But when I got home, the oil level had dropped about 1/2 a quart, and it smelled and felt like it had gas in it. Well I replaced the oxygen sensor and guess what... its STILL FIXED AT ZERO and still has black smoke on acceleration. What am I missing? I sure hope its simple and cheap, and hoping its not the computer. btw.. no check engine light on either. It has the two wire O2 sensor, and one side shows continuity to ground, and the other just shows open, and no sign of voltage. HELP! I dont even know if I solved my oil consumption problem either. The car runs too good and looks to good to give up on it yet.