Check / change your ps fluid ..... also check your reservior for cracks.....
Mine had a similar issue to yours but after flushing the system and new oil it went away after a few 100 kays..
6 speed short shift man with Aluminium cube interior, MTech II bodykit
19 inch Hamann reps with Dunlop SP Sport Maxx,
Factory TV and Nav, upgraded audio with Alpine, Lanzar and Phoenix Gold Components
Individual Colour Tannin Green