I took my car to the dealer for an oil change--and they told me I had two broken motor mounts. I then took my car to a different mechanic to get the problem fixed. After they replaced the two motor mounts, I notice the car vibrates at idle (red light/stop sign)... is this normal? I took it back to him and he said he replaced another mount, but the car still vibrates slightly (steering wheel mostly)...will this eventually subside or should I look into it further? Thanks for any advice.