I've run into a problem where my F2L (like everyone else) is holding me back and i need better look-aheads. I consider myself a really good cuber as far as speed and understanding the cube, and I want to take my game to the next level. Right now i'm trying to average under sub-20 even though i only get a sub-20 every once in a while. Most of my times are about 24-25, but i find when i time myself i tense up a lot and when i can't find a pair i freak out and start crunching on the cube and being really inefficient. tonight i started doing metronome practice and timed myself for giggles. My F2L was still around 15s even though i was moving well under half speed and my times were around 25-27. I was amazed to see that my times were relatively the same even though i was totally relaxed vs. being totally in the zone and moving as fast as i can. Has anybody had this problem or know how to work with it? I can feel im really close to sub-20 but i know im working against myself here. any responses will be appreciated

sorry for the not-well-thought out post