I own a 2015 RS4 B8.. I bought this car in October 2016 and up until now the car has been fine. Two weeks ago the car suddenly stopped whilst driving, and when I tried to restart it sounded really rough. Long story short, the car has been with Audi Belfast since then. Initially they told me I needed new cam shaft sensors, but when replaced the problem persisted. They then told me that it may be an issue with the fuel system or timing belt. However, yesterday they contacted me to say that they advise that the car get a replacement engine! This car is only 3 years old with 40000 miles, and has never been mistreated. They have told me that the new engine is the best option, because the alternative is to strip the existing engine to find the problem, which may take 20hrs labour (£150 per hour) which equates to £3000. Even if they do that, I am being told that they might not find the problem. They now believe that it is an issue with pistons/cylinders. The car was out of warranty in January this year, and I have an extended warranty with Motoreasy. Motoreasy are insisting that the engine be stripped, but are not guaranteeing that they will cover the fault! Plus Motoreasy only cover a maximum of £60 per hour for labour. Either way I am facing a massive bill to get the car fixed. My issue is that I cannot understand how or why this would have happened to a car of this age with this mileage. I also believe that even though the car is out of warranty Audi should cover this due to the age and mileage of the car, as in my opinion, the car had a major underlying fault. I apologise that this is longwinded, but has anyone else ever encountered such an issue with an RS4, and if so has Audi covered it in these circumstances. Any advice would be greatly appreciated.