As it turned out, the Saturn dealer found 3 codes. P0467-"Fuel gauge skewed", P0137- Heated O2 sensor",and P0341- "Cam reference signal". They recommended changing just the O2 sensor for now ($169 parts/labor) and see if the other 2 codes return. They said P0341 is usually caused by defective plugs, ignition wiring or routing. However, the wiring is fairly new and properly installed. The fuel error was caused by a few bad starts I recently had. Long crank time and than started immediately on second attempt. The service manager was not too concerned with these codes. We'll see. They did agree to split the $79 diagnostic charge when I had the sensor replaced today. I was going to do it myself but was afraid it might be seized in the exhaust line. So far, I'm happy. So much for Autozone...