My 2011 Sorento always seem to have a "jittery" sunroof. Open or close it will 'jitter'. I got my spray lub out and opened the sunroof just a bit. I see two rear arms that slide back. I spray lub down the rear of the track with the attached hose... OMG it now opens and closes nice ! No jitter anymore... Yea, I had the dealer look at it and "lub" those front rails with their special lub months ago. This was the back tracks.. two days and no jitter.....