My 06 has been doing that for about 2 years. The code shows, slow response on o2 sensor, bank 1. The light stays on for about 4-5 start ups and then goes out and stays out for a while (weeks to months), then comes back on. I never have this problem in the warm months, only in winter. It has never had any effect on the way my Jeep runs. I have tried to get it to the dealer as it is under warranty, but the light never stays on long enough to get there. Hopefully I'll be passing the stealership one day and the light will come on.