I apologize, I forgot to mention that when the light came on, it drove rough, although that smoothed out a couple of miles after I put in the SeaFoam. I reset the CEL and it did not return. The car has run fine since.
My UltraGauge did show 1399, I just did not use it until after I changed the spark plugs and wires. According to
ActronŽ, it is "Misfire Detected."
My Sergeant says that he earned his ASEs and then realized that he did not enjoy working on other people's cars. He says that SeaFoam is great, he uses it regularly on his truck to get better mileage, but I could have simply removed the injectors and blown them clean.