i used to be on a bmw forum but cant find it

anyway sold my p-reg 328i coupe couple of months ago and i know the guy i sold it to,he says car has developed a problem


it starts and runs fine,but once he braking and the revs drop it cuts out,but starts right away again no probs

he says even sometimes just taking foot off accelarator it does it but burst back into life again itself,

and it has started to idle really low like 500rpm

im not very clued up on managment issues etc,could it be iscv?

anyone encountered this?i know a few have had the bmws