I've noticed a slight judder on idle (even when warm) lately and the car seems a bit lazier when putting my foot down although that could just be me imagining things. No engine light on idle or during driving. The previous owner told me spark plugs had been changed but there is no proof. The mileage is 60k so I'm thinking as a first port of call replace plugs and I'll try to get any fault codes scanned (not expecting any to be honest). Do the ignition coils have a replacement interval? I've checked and it's around £130 for a set but rather not spend if I don't have to. Appreciate any other pointers.