I'm no mechanic but if your engine were running closed loop all the time it IMHO is probably the OBC module and you should notice it.
I posted a similar question about my 04 Lariat 60k 5.4 3V light was on. Gages hesitated to register and bounced a bit at start up. The digital trip, gas mileage, etc.. info would reset. I was thinking gremlin....
It was recommended I check the battery. Sure enough, original battery from MotorCraft. Replaced it a few days ago with Interstate Megatron and all has been perfect! Worls of differnece.