Can anyone help? Our 2013 multijet went into the main dealer for a service. On return my wife reported a loss of power and a howling/ whistling sound. Back to Fiat. They say they had disconnected the pipe from the air filter to the intake at the front grill. They refitted it. Out on the road and it did it again. Every time I put it in, it is blow out again. There must be excessive pressure somewhere to keep doing this. Has any experienced this before? Thanks