I actually have a fairly good idea of why you have trouble with the metronome, LH-if you are playing a strum pattern, like say, the famous Dylan strum(which is really a Ramblin' Jack Elliot strum, at least in my opinion), you are keeping the beat, not following the beat--since the metronome doesn't listen, it doesn't know how to follow your beat, and goes it's own way.

What you have to do(at least if you want to be in sync with the metronome) is to stop keeping the beat and refigure what you're playing so that it follows the beat. It opens up you playing when you stop keeping the tempo and can concentrate on doing other things--