Hi guys. Wondered if anyone can help or if they’ve had the same problem. I have a 62 plate Astra van 1.7cdti. When on idle it seems to hunt a bit, so I got the fuel filter changed. Seems to have helped a bit but I also have a strange whirring noise. Starts low and then the noise gets Higher and then stops. Does it when cold on idle and also when driving. Seems to quieten down when warm. Sounds like it’s from the high pressure fuel pump area. But the van drives fine, no lack of power or cutting out or anything. Can anyone help or know what the noise is/ If it’s harmful to carry on driving. Thanks in advance, Tom.