Hi - this is my first post so please go gently. I have a 53 plate 307 HDi with 90 horse power. I had new diesel plugs and a new battery because of poor starting three weeks ago. Since then it has idled really badly. I've taken it back to the local garage that did the work and they said it'll take 3 weeks for the ECU to learn how to work again. I've driven it through the rev range over the weeks but it still idles with a really dirty noise and is using loads of diesel. Should I try and disconnect the battery again or is there something else wrong? Could they have used the wrong plugs? Any longterm damage? Please help?