The stock MINI leads are a bit temper-a-mental! Basically the quality is not great and if you take them on an off a few times they seem to get damaged and so they don't let a decent spark. One way to resolve it was to fit the
JCW leads (they are blue not the stock black), or buy Magnecor leads. I got race spec reds as my cars fairly tuned (plus I like red, as Dave will grimace and nod in agreement of
)
Unless you have a problem again I'd not worry too much, just bear in mind to change the plugs every now and then and look at the leads if you have problems and yours runs stock ones
