With Connecticut my home town, I understand the whole island thing since I visited there allot.
If you have a ohm/volt meter, it's easy to find the problem. You can pick up a cheap digital for like $10-20 from radio shack or similar source.
First, try reseting the PCM (Unplug for 5-10 minutes) and try reseting the code. If something fouled up the exhaust stream (Bad fuel) and the O2 sensors displayed something unrealistic, the PCM will fault them out and run in a open loop mode. Reseting the computer will force it to try using the O2 sensors again, if they fault again, look further.
So, physically check the electrical connectors to the O2 sensors, check for Mud/Corrosion, a bad connector is just the same as clipping it off.. You only have 2. One o2 monitors the Exhaust directly out of the Engine, the other monitors the CAT performance.
Disconnect and Ohm across the two white wires on the O2 , should be 5-7 Ohms.. replace if otherwise.
With the unit hooked up, measure the voltage on the black and Gray.. should be between 0v and 1.25v.. and moving.. if flat 0v or similar, replace..