My ’89 S4 has Pirelli P7000 on them. The car drives best with the Porsche recommended tire pressure: front 36 psi and rear 44 psi. The computer started warning me about a week now about “REIFENDRUCK VERLUST” (tire pressure loss) on the left rear side. The pressure is still 44 psi when I measure, and when I deflate a little and inflate up to 44 psi again the remark is gone, only to appear the next day (mornings AND evenings). Seems a sensor thing to me. Anyone got any suggestions?