Just used about 3/5th can of Seafoam in my del sol. While slowly vacuuming seafoam into the engine through the brake booster line, I noticed a good bloom of smoke coming from the back. I shut the car off and waited five minutes, idle for about 30sec and took off with a puff of smoke, but it was pretty clear after that. Just wondering still whether the smoke is carbon or oil, because putting oil through the injection fuel system in that method would still result in similiar smoke.