Its a small item but it was turning on the check engine light repeatedly-- trouble code P0341 - camshaft position sensor A performance bank 1.
So I ordered it on Amazon for $30 (I know ouch) and installed the new one today. Cleared all trouble codes and will be watching the car very closely to see if the check engine light comes back on. Here is a pic, you can see the old sensor on top of the engine cover.
While I was doing that I also discovered a cracked emissions hose. I don't know if it was already cracked or I did it while I was installing the sensor. But anyway, this hose was as dry and brittle as a piece of uncooked spaghetti! But the car is 17 years old so I guess no surprises there. Anyway we went ahead and replaced that as well, so perhaps that will take care of one of the other trouble codes we saw today, which was P0105 - manifold absolute pressure/ barometric pressure circuit.
Did the repairs then took it out for a spin around the block and everything seems fine, no check engine light. Fingers crossed that fixes it. Also, Yuji was pretty happy with my repair skills and made me this certificate of awesomeness. Thanks dear!