SD Z4MR, I agree with Kurgan. Change the filters while you're doing it and the plugs as well. You might want to even consider new ignition coils, since those can die around 30K (or so it seems).
Since you're in San Diego, you might want to contact Kevin who does mobile valve adjustment work. It's his specialty, and he comes to you. He's Kaiv on the forum. Here's
a thread from Rclem where the job was documented and discussed.