maroon, my 85 240 automatic is too old for a check engine light. It developed a nagging problem just after cold startup. Two minutes after start the power went to nearly nothing, but engine never quit. About 30 sec later or maybe a half mile, something would "turn on" and everything was fine. Checked everything I could think of. Began to suspect the Ox sensor. My computer geeky son said simply disconnect the two wire connector to the sensor, not the single "heater" wire. The computer will simply ignore not getting its Ox sensor data. The problem went away but I did notice a power loss. IPD Parts in Oregon has several Ox sensors depending on year. The sensor for my 85 was about $75 plus shipping. Autozone has an ox sensor socket for about $10 with the slit in the side to go over the wire. Sensor should be accessible from the top/underhood. Amazingly it came loose easily. Used anti-seize from spark plug changes on the threads and the new one was back in in about 10 minutes. Problem solved. The sensors do go bad after time and miles. They say 50K or so. Mine had at least 100K on it. My bad. Hope this helps.