O2 Sensors Bad?

[Fox89GT]

For one thing, how many miles do you have. My guess is that it should be change after about 60-70k miles but I still have mine at 90k. I'm planning on changing it soon because my Check Engine light blinks every once in a while when the engine is cold under moderate acceleration.

In your case, I think your engine is running too cold and never getting up to optimum operating temperature, therefore, causing it to run a little rich. Try changing your themostat back to a 190 degree one and then check your mileage.