I have a bmw e46 318ci coupe and it starts fine. however when it reaches a certain temperature it keeps cutting out. It restarts straight away and sometimes needs a few attempts. Hoowever once it gets to the half way mark on the temp gauge it works fine and no further problems but in between this it will cut out whilst accelarating even in 4th gear or even when sat in traffic in neautral. No lights have come up no engine management or readings found when connected to bmw machine. What could it be.