I have a 2005 A4 1.8t Cabrio which has just started to play up, I will tell you what has happened and what I have found so if anyone can shed a light on the problem that would be great........... Recently I went out in the car on a short journey (less than a mile to collect someone) just after leaving home the engine started to mis fire and shortly after the engine management light came on. Usually around 2000 rpm you can here the turbo whistle up but on this occassion I didn't here it. That may be a red herring. I got to where I had to go, switched off waited a short while then my passenger arrived and we returned home slowly, the car still mis firing. On lifting the bonnet I saw the CAT glowing rather hot (Bright orange CAT and Dull orange heat sheald). I have since removed the air filter so as to replace it and the plugs, Number One was still wet but not exessivley. Is there a way of checking the coil packs out of the car using a multi meter? Could the CAT have collapsed causing it to over heat? if not what else would cause this? Would this over heating damage the Lambda sensor and or the CAT? If the car was mis firing would any un spent fuel burn off in the CAT causing it to over heat? So many questions but hopefully some out there can throw some light on it, maybe this has happened to you. Anyway, if someone could help me and maybe give me some ideas on what and where to check it would be greatfully apprieciated. AL.