Smoke coming out of the exhaust 4 different times as I was driving I would feel the car go a bit ruff then smoke foot down smoke and a bit limp or missing then after 30 seconds to a minute it would go back to normal fine for a few weeks then same thing no engine lights or codes then today service and MOT emissions perfect but the oil level on the dipstick was higher than it should by about 3lt even though nobody had put any oil in since the last service and MOT and still no lights or codes

Which engine does it have?