Hi wondering if anyone can help. I've got a audi a4 57 plate 1.9 diesel. It's making a chugging noise like air chugging if you lift the top of the airbox you can hear thr noise louder. When driving it sounds like I've got a blowing exhaust. Car drives fine no loss of power. Had it plugged I no faults found. Its driving me mad as I've had few people look at it but noone can seem to find the problem
Thank you