Had my S4 remapped last week, and as promised the car had a lot more oomph to it - particularly a noticeably bigger 'kick' once the turbos had spooled up. The engine checks showed up the exhaust gas temp sensor needed replacing but I didn't have time to wait for a replacement and he wanted £200+VAT anyway - I wanted to get my local specialist to do it as I know his price will be right. He said this wouldn't affect the remap. For about a week it was great but halfway through a 100mile drive yesterday it seemed to lose its edge and feels almost like it's reverted to factory settings. Could this be anything to do with the sensor? No warning lights, engine accelerates nice & smooth as ever - just a bit mystified. Any thoughts anyone?