2001 4.0 4x4. Automatic Got the p0300 code for random misfires. Just did the tune up and it's still reading the same code
and have a p0705 code transmission range sensor. It changes gears fine and the needle indicator moves with the shifter

 

"Tune Up" can mean a multitude of things.
Did you change the Plugs, Wires, CoilPack?
Is it possible you've got swapped ignition wires?

Click here for more info on V6~4.0L~SOHC ignition system.

 

How many miles are on the vehicle?
If I got a P0300 post tune up I'd look to the wires and coil for cracks and age.
No idea for the trans code.

 

P0705 Transmission Range Sensor Circuit malfunction (PRNDL Input)

On the transmission, driver's side, you will see the DTR(digital transmission range) sensor
Looks like this: https://www.explorerforum.com/forums...d-jpeg.177416/

When you move the shifter in the cab a cable moves the shifter on the transmission, and the DTR sensor tells computer what "gear" driver selected

Common issue on all Ford trucks is a loose column shifter, Google: ford ranger column shifter loose
Usually just loose screws
Or could be DTR sensor is broken, or out of adjustment
Unplug the wiring connector and check for corrosion, then plug it back in, clear the code then see if it comes back

 

I changed the plugs and wires only
Mileage is 139k

 

Clean & OhmCheck the CoilPack.

 

What Make#Model plugs did you install?

 

It's 4 clogged catalytic converters... They're going to eliminate 3 and straight pipe the main cat. Still 800 bucks but it'll be ok. I've spent more for less lol

 

Eliminated 2 cats, replaced the other 2, not much noise to it even with the glass pack on it, changed the coil pack and the oil pan gasket today and still has a rough idle. Check engine light hasn't come on since though. Can't figure it the rough idle though...

 

What Make#Model plugs & gaps?

 

Can of Seafoam in gas tank once a year smooths out my idle

Yes, check gap on spark plugs, 4.0ls use a pretty big gap, 0.054