Didn't notice you had more then one thread going, both the links you posted are to the same thread.

Anyway how about the ACT and ECT sensors and O2 sensors, how old are they? original to truck? If you listed any of them as being replace sorry I missed it.

To an extent the symptoms you describe tends to suggest a rich condition, what do the plugs look like after run a few miles? Looking at the plugs will tell you a lot about the conditions in the combustion chambers.

Ruff idle, horrible gas mileage hesitation that goes away under heavy and or full throttle conditions suggest rich condition, all the fuel its getting is consumed under that condition, at idle/part throttle to much loading it up.

The fuel injector you blew compressed air through, did you apply constant power to hold it open it or rapid, fast as you can on/off/on/off/on/off power to it. If you applied constant power holding it open you likely damaged the injector, it could be constantly dribbling fuel as a result.

ACT could be reading wrong as well as ECT telling the computer its running "cooler" then it really is, couple that with an ole dirty carboned up 02 sensor making a bad condition worse. None of them bad enough to trigger a CM code.

Of course some test can be done to see if sensors are within acceptable range.

How about fuel pressure test results including the static pressure leakage check results?