The engine is not running smoothly - it is juddering when idle and when I start the car from cold white smoke comes from the exhaust like an oil burning smell. Was told it could be a leak on the seal of fuel injector by a friend who is a mechanic but does not have the tools to repair. Have taken it to a Hyundai garage but they cannot find anything wrong on the diagnostic check and want to strip the engine to find the problem but is going to cost a lot of money before they even find the fault. They are telling me it could be a much as £1000 to repair when they do not even know what it is.