2004 Ford F-150

Is your check engine light on? What code(s) come up during the scan? 02 Sensors are only recommended 50,000 mile change, if you have no drivabilty concerns, why would you change them?

Those are codes for the upstream sensors only, they are the first sensors from the engine. Which 6 do you have 3.0 or 4.0? Could be a vacuum leak problem if it's 4.0, check with a can of gumout spray, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! If you find no leaks replace the two front sensors, one on each side.