One of your calipers might be seazed. Mine did something similar. The pulsating was related to speed, not gear, and got worse if I was on the brakes.

Eventually it ate the pad and rotor up.
I removed the caliper, took the piston out, gave it a good cleaning and sanded lightly with 800 grit.

Replaced all 4 rotors and pads. Everything's been perfect since.

 

OK, I will be looking at my car tomorrow morning and reporting back...

 

Still have not had time to diagnose the problem. I think I'm going to have to remove the axle and see if the wheel bearing grinds when rotating the wheel.

 

Heh, I had that problem. It was scary because I thought it was the wheel bearing.

 

Maybe I'll inspect the brakes tonight???

 

Wow. On an 05? That's surprising. They have better brakes.

 

Took the drivers side rear brake pads out and they are both the same thickness. I can push the caliper piston in with a C-clamp. I still hear the noise over 40mph+!

 

^You could still have a warped rotor... or it could be a wheel bearing.

 

The rotors and pads are only like 2 years old, they actually look pretty good, almost brand new.

I guess my next step is to remove the axle and rotate the wheel to see if it grinds, like my other wheel bearing did.

 

I'm having the same issue. Did you ever find out what the problem was with yours?

 

No, I didn't. I have noticed a smell from that wheel after a period of highway driving though.

 

^Does it smell like brakes?

 

Not sure what brakes smell like. Haha How can I diagnose a stuck caliper? I removed it and everything looked normal.

 

^Kinda like burnt clutch

Go rent a Kia, set the parking brake, and drive around town for an hr or so... that's what brake smells like

If the caliper is stuck, it will be really hard to push the piston back in.
You might have to take off the other one on the back so you have a frame of reference.

 

i have an 04 coupe 6mt with brembos and i'm getting this sound from the pass front. definitely worse on highway and starts above 40mph. doesn't change a whole lot with speed from 40 to 60 though. did you ever figure it out?