Po152 hhhheeelllpppp

[426H300SRT]

So, after a complete disaster with the MSDS cam wipeout on my 2012 SRT 300, I now own a 426 6.4-based Hemi, built locally through a very good and reputable Hemi guy here in Cleveland. after a couple of good pulls on the dyno. It was recommended to correct a couple of issues prior to the next visit. The car was running very strong up until about 700 miles or so. When I began to get the PO152 code and cylinder 8 misfired code.
at this point, I replace bank 2- sensor 1 O2 sensor as well as coil pack 8. uploaded the tune once more, and the car ran fine for a day and the same code 152. Data logging shows the right bank running extremely rich. WHY ?????
swapped injectors from side to side, no help; sprayed starting fluid all around the manifold, no zoom; zoom. no injector leaks, a very minor exhaust leak north of #1 sensor, removed cats, disabled rear O2's no help.
The tuner is very interested in helping me over the phone and data logging. I have yet to look at plugs but will do so tonight. can reset the codes and retune drop and runs good for a day with the exception of smelling rich. any ideas Please

[Team_hellcat]

if you have headers could be the extension for 02

[426H300SRT]

OK, so I looked at the plugs, and for sure they are rich on the entire bank, more so on 8. New plugs were added and swapped the 1/1 O2 sensor with the 2/1 O2 sensor NO CHANGE when looking at Data, 1/1 bank volts at between 3.25-3.65 good right well bank 2/1 volts are 4.70-4.95 never below 4.70v. Before I order a new ECU, PCM, or ECM is there any way to test the injector pulse or see if it is a bad driver for any one cylinder? Again, I did swap Injectors from side to side NO change.

As for headers Yes I do have them as well as an extension cable but I've had them for 4 years. rear O2 sensors are no longer in tune and they are the only ones with extensions.
thanks