Basically every time i put my foot down on the accelorator i hear a whistling noise.

I had an MOT & service last month, i mentioned it too him, he said its common with fiestas, tbh i think he just said that...

I had it before and it went a little bit for a while and now come back,

what could the problem be?

Thanks

Chris

(fiesta 1.25 zetec 95 plate)

Turn the speaker volume up and down whilst nothing is on i.e. will work best if you put it on AUX and put the volume to full and start revving your engine. Unsure why cars do this but they do.

yep mine whistles on the AUx input all the time. Although can only hear it if the volume is up quite high.

Thats RFI / interference from the ignition (usually the ht leads) breaking through to the input of the amp in the head unit (either air bourne or through the wires) better earths or ferrite chokes (rings) can help if thats what it is

It's only noticeable if the volume if high and nothing is playing on AUX, not on FM or Bluetooth.

Don't use Aux port, the Bluetooth is very high quality and just starts playing in a few seconds, pretty much the perfect set up.

Definitely need ferrite cores on your aerial and aux cables.

I found mine did the whistling trick when using the aux connection and revving up.

The cores stopped it quite nicely.