Clio cup172
Hi all my 03 cup 172 has started to mis fire when cold so changed the spark plugs not made a difference I put a timming light on the leads that go to the coil pack and the two back show a mis fire but the front two are fine are the two back and the two front separate in the coil pack or are they all linked does this mean I need a new coil pack also the engine management light has also come on if anyone can shead some light on this please 
