I have posted before about the car vibrating a tiny bit when idle so I was thinking maybe my idle speed is off. What rpm is every one's car idling at?

Also, my brakes make a thumping sound when its rainy outside. I can hear and feel it when I release the brakes. This only happens when it rains and when I am release the brakes and begin to drive, any one experience this?

On the second question, this is a well-known (and searchable...) item; overnight your brakes can get damp, get the light rust coating and stick. The "thump" is the brake pads unsticking - should go away after the first roll.

The car does seem to have just a hint of vibration when cold, but once it warms-up, it's smooth as silk.

My car's idle is just under 1K RPM (850-950) when warmed up. When cold, the car idles around 2K RPM then ratchets down to just under 1K RPM in a couple of minutes. I always let it warm-up before taking off, just to get it's blood circulating good. I have also noticed that if you step on the brake before it's warmed up, the idle will come down to around 1K RPM to minimize shift shock on the transmission when shifting out of park.

I am talking about when the brakes are wet or when its raining out.

Interesting, mine idles about 650 or so. I noticed yours is an S and mine is an X. Can some one with an X chime in and share their idle speed.

I dont know how I feel about his "rust" explanation; I get what you're talking about after a pressure car wash...

My 1 month old X works just like MojoKidd's. 1k after warm up and 2k at startup except pressing the break during warm up does not drop the RPMs untill after I put it in gear.

Next time you wash your car, at the end look at your rotors - they've started showing orange. Mine do, in the course of a 45 min wash.

Think about it, our rotors are the rawest ferrous metal out there. They are continually scraped clean, so the surface has no coating whatsoever - rust begins instantly in the wet.

You can also look at cars at the dealer, even brand-new ones will have orange on the rotors.

what part of your car vibrates

?? You said "it only happens when it rains, and I release the brakes and begin to drive." Guess I wasn't clear that when your brakes get wet, and the car is stopped for a while, they will sometimes stick and release with a thump when you start driving. Apparently I used a hard-to-follow example...?