ive had real probs with mine today its started running lumpy on tick over and if at low speed its very jerky again ,does anyone think it would be a good idea to replace coil pack and leads plugs as everyone says the coil packs do go bad on these, help I don't have a lot of money and realy hope this is the fault ,when over 4k it drives amazing and pulls well but anything under 4k then it drives realy lumpy