On this site, we often tell intermediate musicians to slow things down and practice with a metronome to establish a good sense of time. I have the opposite problem. I spent my college years practicing everything with a metronome and writing down the tempo of each exercise in a practice journal. As a result, I feel a little stranded without it, and when I sat down to play my scales this morning, I was surprised to find that I couldn't "remember" my comfortable speed without referring back to the metronome.
What generic exercises can advanced musicians use to reduce their dependency on the metronome?
I have occasionally done the one where you set the metronome to cut out for a bar and try to come back in on the beat, but the main purpose of this exercise is to improve your sense of "external" time (your ability to match an externally imposed meter and play in time with other musicians).
I am looking rather to improve my "internal" time, i.e. the ability (in a rubato context) to traverse between tempos in a way that's expressive and controlled and (in a nonrubato context) to start out at the right tempo without referring to a reference beat.