The garage looking at the loss of power + backfiring on my '92 525i Touring (M50 engine) has told me their diagnostic equipment has reported back an '85 code'. I assume this means a 1285 code. They don't know what this means and this code doesn't exist according to my Bentleys manual. (I couldn't do a stomp test as it's a UK car and my understanding is that European spec cars don't have this feature available).

The garage thinks the problem might be a faulty cat - they are going to take the car to a BMW dealer tomorrow for them to test. Before they carry out this potentially very expensive (for me!) exercise, does anyone have any ideas before I'm asked to part with a bucketload of cash..

Thanks