When car reaches operating temperature it starts to rough idle

I would be looking for a vacuum leak. Check that none of the hoses have been split or disconnected when you were working on it before.

Sounds like you've done everything but the injectors. Run a bottle of fuel injector cleaner in a tank full of gas every time you do an oil change after this time. Also, check the fuel pressure to see if it's where should be for the injectors. But then, if it has enough pressure to go through the dirty injectors to make it run, pressure should be good. Check it anyway.

Does the truck seem fine when you first start it & then acts up when it reaches operating temp?
That would lead me to look at my oxygen sensor, a bad sensor can cause the truck to run "rich" which would explain the fuel smell in the exhaust.

Spark Plugs have to be changed every 3 years
Front Oxygen Sensors changed every 100,000 miles
Can't have any Vacuum Leaks -- anywhere on the vehicle
Need to have it road tested with a Professional Scan Tool
& look at all data & get caught up on Preventative Maintenance
Very few people change motor oil 3 or 4 times a year, if at all,
and the Variable Cam Actuators fail, as a result,that & few other
things can cause rough running engine & resulting idle issues
It's well known that Ford COP Ignition Coils fail sometime in
every year of ownership

Okay, lets start with the oil you found on spark plugs when you were replacing them. this oil is coming from the valve cover tube hole area, notice the plugs go into the holes in the valve cover, there is a gasket the goes around the top of the tubes and when it leaks it goes into spark plug hole, the valve cover needs replacing .
this will cause rough idle and running problems, after replacing valve cover gasket the holes must be cleaned, using crab cleaner, spray into holes and use air to blow out . this may need to be done a few times to get oil out .
after oil is removed . then remove spark plugs and wipe them clean.
The next step is to find the air (vacuum leak) , you said you hear it around intake tube. check for cracks or broken vacuum line. this leak will cause idle problems and driving problems,

Chances are you have an oxygen sensor problem. When the engine warms up, the engine computer moves from open loop operation to closed loop, and it then uses the O2 sensor readings to adjust the fuel. If the sensor(s) is contaminated, it will send a false reading to the computer causing this problem.

sounds like a bad idle air control valve, but if its misfiring thats another ball game,then you may have a bad spark plug or plug wire.when was the last time this car was tuned? if its been a while then you may what to start with a complete tune up, also have the fuel preasure check as this would also cause this problem but if it rides fine and only runs rough at idle then its not the pump.now we are back at a tune up.

check for a small vacuum leak speciallythe lines going to the throtle have someone look at it while you seat onthe car , idle ,FOOT ON THE BRAKE ! a way to test for leaks if to spray a lil wd40 around the lines an listen if the idle gets better or worst, sometimes the reason the engine runs to rough or lean are vacumm lines that are slightly broken.

sound like intake leak. get a scanner to see if egr valve not staying open . check map sensor + make sure the vacuum line didnt come off it . check coolant sensor. oxygen sensor .check fuel pressure regulator. check vacuum line that goes to fuel pressur e regulator . make sure there is no gas in it. make sure its getting vacuum. check pvc valve.shake it make sure it rattle .