Open / Closed Loop Issues... and more

Having a hard time sorting through all the data to troubleshoot some issues I am having. I will try and keep the description short and clear... but I have many other numbers I can share if questions come up. All data is from Torque Pro app running as I drive.

Only codes I have are P0171, P0174 and P0306.

Problem: Rough idle and bucking or no power. 98% of the time at cold start, but has happened twice during "normal" driving. Once on some climbs at highway speed, then again up a mountain pass at low speed.

Solution: Stop the truck. Turn the key off for 2 or 3 seconds. Restart. Boom... runs all but perfectly.

Some data anomalies...

Have noticed the following on cold start:

• Goes into "closed O2 loop" almost instantaneously. STFT begin rising and falling somewhat normally (single digit swings)
• Time varies, but in less than two minutes, "open O2 loop due to load". Power drops off, idle becomes very rough. As I drive, engine warms. Power issues persist and eventually (around a minute or so later) O2 message will change to "open O2 loop low temp". This open loop status will remain even well past operating temps are reached. Truck will not leave open O2 temp loop status until I turn off the motor.
• STFT drops to zero and does not come back until key is switched off.

CAT Temp sensors:

• B1S1, B1S2, B2S2 and B2S2 CAT temp sensors will all read 950 to 1100 degrees (on average) right at startup and will stay there for about 4 seconds. Then all will drop off to basically outdoor temps. From there they will rise until...
• At a certain seemingly random point (engine temps around 100, about 2 minutes in) B1S1 and B1S2 CAT temps will start to drop. Example... drop from 940 degrees to -.40 in about a minute. Then rise back up to around 66 degrees and just sit there until key is switched off. B2S1 and B2S2 temps trend upward steadily during this time.
• After key is switched off... CAT temps "equalize" and all rise gradually and steadily while driving.

Questions:

• What might cause the vehicle to basically start in "closed O2 loop"?
• What might the key switch off be resetting?
• Are the O2 sensors responsible for sending CAT temp data?

Any guesses, input, places to look next or patterns to seek out would be greatly appreciated.

Thanks