I wanted to give an update on my 07.

Was out of town for a few weeks building the house in Arkansas plus a few car projects will there. While up there I unplugged the battery as mentioned and when I got back to try it the long term offset for bank 2 was gone. After this result I was wondering if the situation would come back even though the STFT's for both banks looked the same.

I decided that with 60K miles on the car I was close to the time for replacing plugs and there seems to be limited life on the coil packs, so I decided to move on with a major service of plugs and coils. Parts aren't in yet but was quite pleased to see that on back 2 cylinder 8 the plug was in poor shape. This confirms I was on the right track with the issue on cylinder 8. At least a major service will be out of the way and I will have spare parts to help with trouble shooting in the future (except cylinder 8 parts).

I want to build up to testers that will allow me to run injectors out of the car to check pattern and one to check the coils. I haven't yet been able to find info on how to ignite the coils such as what needs to be supplied to each of the 3 pins and if I need to add a capacitor to supply enough current to the coil.