Hi, i have been havng trouble with the running of my Lupo 1.4 16V ever since i bought it. The plugs have been oiling up causing the car to miss fire. also the Oil light is coming on when the engine is hot and i am driving the car between 1-2 x 100 revs, but goes if i accelerate. i have been told that the piston rings may have gone and this is why i am getting this problem. Is this a common fault?????????