In the last couple of weeks I have been experiencing some some issues with my r53. To begin, about a month ago I had a 15% pulley, JCW fuel injectors and a tune installed. Everything was great until a couple of weeks ago. I have been experiencing a random rough idle. Everytime I start my car when it's cold the belts squeak until the car warms up and that goes away. I have also experiencing a vibration/tapping sensation in the brake pedal during idle only.

I spayed some WD40 on the belt tensioner and the belt squeak goes away.
Does this sound like a bad belt tensioner or do I have a much more serious problem?

 

Make sure you crank pulley isn't failing, we've seen a lot of them lately and been replacing them with the improved ATI damper.

 

Well you were right about it being my crank pulley.

On a side note, I was hoping I could get your opinion on another subject. I am waiting for you to get the OEM Lower Motor Mount in stock and I have been contemplating getting the Powerflex polyurethane inserts. My Mini Cooper S is my daily driver and I live in Minnesota where it gets quite cold in the winter. Would it be a bad idea to use those inserts?

 

Is that on the stock crank pulley? I've heard that after a long time the rubber that holds the two pieces together will actually fail. Not sure if its true.....I'm sure someone could confirm.
Like WMW said you can go with the at I dampener. Not sure how its been performance wise compared to the light weight pulley upgrades. That's the route I went and haven't had any issues at all for 30k miles plus.

 

Yes it was an OEM crank pulley. I am just going to replace it with another OEM pulley.