Mine is doing something very similar, just with no code.
I tried to spray on carb/brake cleaner on the hoses... doesn't appear to be a vacuum leak anywhere. With the mileage on yours and age, it's probably not a leak due to age.
Try cleaning the MAF. If it's not those, I'd suspect the front O2 sensor at that point.
**If you have an AP, do a datalog for your AF learning 1 (all values, A, B, C, D and 1). Positive numbers are probably what you are going to see and indicates the ECU is dumping more fuel in. I suspect your numbers may be very near 15% as that is the max the ECU can compensate.