Hi All Well just sent the car in 4 a M.O.T and it failed on the lambda readings. Well i have changed the oil,fuel filter, air filter and the plugs, also changed the lamda probe aswell as cleaned all the points of contact inside the distributer cap the leads all seem fine yet there is this misfire which comes and goes but is quite often. I know it needs to go on the diagnostic machine but was wondering if it could be something common and simple Thanks