I purchased a second hand 2008 (58) Mini One (petrol) two months ago from a private seller. Everything had been great for the first few days until the car started to cut out in first gear when I was waiting to pull out at a junction or island.

I took it to the approved MINI garage who told me that I had very little oil in the engine - they topped it up and for the next week everything was back to normal.

Ever since then I have been driving the car short distances to work and back but whenever I pull out at a junction, island or sit in a traffic jam the engine splutters as if it is going to cut out. There are varying degrees of spluttering, from just a small 'cough' to a full 'shudder'. I have taken the car back to the garage but they tell me that the car is perfectly fine.

However they told me the most likely problem would be my spark plugs but that they were working well. However they did put an additive into the car anyway so as to try to get rid of the problem by cleaning out the engine. This has not worked and in fact the spluttering is getting worse. It happens every time the engine is cold and it does not seem to be affected by outside temperatures.

I have taken the car for a long run to try to clear out the engine but the problem just returns the next day.

The garage says that there is no problem but both my father and I have witnessed the spluttering first hand and we both agree that there is something wrong with the car. I was wondering whether you may be able to provide me with an idea as to what it could be as I am worried that the engine will cut out completely on me at some point.