02 sensor full throttle test /on road test

HELLO,
I WAS WORKING ON 2010 FORD F250 5.4 L NO POWER COMPLAINT.I FIRST PERFORMED THE WIDE OPEN TEST TO MONITOR MY 2 FRONT 02 SENSORS . FOUND BANK 1 GOES LEAN ON PASS. SIDE AND BANK 2 GOES RICH ON DRIVES SIDE .LEFT CATALYTIC CONVERTER WAS ORIGINAL AND OTHER SIDE WAS AFTER MARKETED. I WAS NOT ABLE TO PERFORM BACK PRESSURE TEST BECAUSE BOTH FRONT 02 SENSORS WERE ROUND OFF SO I WENT BACK TO THE 2 FRONT 02 SENSORS .( MY VACUUM GAUGE WAS BROKEN SO WAS UNABLE TO USE IT TO CHECK FOR A CLOGGED EXHAUST.) THE TRUNK IS FIXED FOUND DRIVE SIDE CAT CLOGGED AND RIGHT SIDE FINE. MY QUESTION IS WHY DID MY RIGHT FRONT  O2 SENSOR GO LEAN AT FULL THROTTLE? I TEST RIGHT SIDE FUEL INJECTORS ALL PASS . SMOKE TEST PASS . DO NOT REMBER WHAT THE FUEL TIME WAS SORRY. THE LEFT SIDE CAT WAS CLOGGED 
100 % AND THE 02 SENSOR STAYED. HI WHICH I  UNDER STAND BUT WHY DID THE RIGHT SIDE FRONT CAT GO LOW AND CAT WAS NOT CLOGGED. REPLACED COMPLETE Y PIPE WITH CATS FROM FACTORY $1800 INSTALLED 2 NEW FRONT 02 SENSOR ROAD TEST TO SET ALL MONITORS ,TRUNMK RUN GREAT. WHY AM I MISSING ON MY DIAG.     PS. NOTE AT FIRST ROAD TEST CAR WOULD NOT GO OVER 30 MPH
THANK YOU RAY 

Hey Ray! I moved your post to the Repair section.

The bank one upstream O2 on your Ford showed lean during WOT because of the plugged cat AND because of the MAF system used on that engine. Think of it this way: Let's say at WOT the MAF was measuring 150 g/s of air going into the engine. The ECM assumes no mechanical or breathing issues and will then divide that by two, or 75 g/s for each bank. It'll then add a proportional amount of fuel by adjusting the injector on-time.

But your Ford had a badly plugged cat. That means the airflow through each bank wasn't equal. Instead of 75 g/s through each bank, it might be more like 50 g/s through bank two and 100 g/s through bank one.

The ECM doesn't have any means of knowing there's an imbalance in airflow across the banks. So it added 75 g/s worth of fuel to bank two (reality is 50) and 75 g/s of fuel to bank one (reality is 100). Bank two runs rich, bank one runs lean.

EDIT: For anyone else that hasn't seen this before, this is a shot from an '02 Crown Vic that also had a plugged cat. The WOT starts right before frame 200:

 

Thank you
for the information it all make sense now .