Got a 99 5.2l 4x4

I have no issue first in the morning driving about 20 miles highway/regular streets mix. When I leave for lunch one of the following scenario's occurs.

-Start the truck up and sit at idle with in 5 minutes it will start to die, you can punch the gas pedal and the rpms raise as they should and then it will go back to sputtering. If I shut the truck off and restart after a few seconds it will operate as normal.
-Start the truck up and let it idle for a few put in gear and drive off, then the truck starts sputtering like the above situation and this happens within 1-2 minutes depending on driving conditions, i.e. driving through a parking lot with traffic, bunch of start/ stop and not getting into second gear. Also if it happens while driving the more gas you give it the more sputtering it does, if in neutral or park it acts normal but will continue to sputter. Shut the truck off and restart it will act as normal.
Either scenario will happen for any other trips during the day if the vehicle has sat after a drive for 30 min or more.
I am hoping it could be a sensor that is acting up, and I have replaced the transmission output sensor after this issue started.

 

Unplug the front O2 sensor, and see if the problem persists.

 

@HeyYou did that and it ran fine, so I changed it out and it is all good. Thanks for the info. Weird that it did not throw a code until it was unplugged.

 

O2 sensors have a variety of failure modes that don't set a code. The PCM simply doesn't know it is being lied to.