My car had been skipping and misfiring. Then last Sunday white smoke and gasoline started coming out my tailpipe and it wasn't holding pressure. It also had the smell of gasoline. Had it towed to the shop and they changed the gaskets, oil, spark plugs and seals. Got it back the next Wednesday and it drove great for that day except for when I would stop it would vibrate and the oli light would flicker until I started to drive again and then it would go off. Then thurs it got worse to where the oil light would stay on . Now today, Friday, the white smoke came back with the gasoline out my tailpipe and the car keeps cutting off. The car isn't over heating but the coolant kind of bubbles up when you give it gas and the check engine light stays on which read codes for an o2 sensor and knock sensor. Just stuck at a dead end. Any clue or help would be really appreciated.