Random Misfire on 2 & 3

no info generic answer if you have injectors most likely dirty or failing

I would start with the inlet manifold gasket, these are know to break down causing vacuum leaks which can cause this issue, also check around engine for other vacuum leaks

remove and clean the injectors
misfires are more injector problems than wires and plugs

change the spark plug and then the coil, if it still misfires, it is the injector what you should do first, move the spark plug from that cylinder to another one, and use a scanner to see if the misfire follows to that cylinder, if it doesn't then your problem is in the coil/spark plug wire, and if a new set still does that, your injector on that cylinder is partially obstructed.

PO300 - Random/Multiple Cylinder Misfire Detected

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crankshaft position (CKP) sensor (POS) signal to vary, Powertrain Control Module (PCM) or Electronic Control Module (ECM) can determine that a misfire is occurring.

Causes:
- Improper spark plug
- Insufficient compression
- Incorrect fuel pressure
- The injector circuit is open or shorted
- Fuel injectors may be faulty
- Intake air leak
- The ignition signal circuit is open or shorted

Solutions:
- Perform Injector Service
- Replace Spark Plugs
- Replace Injectors
- Replace Ignition Coils

If it was a specific misfire code go to that cylinder and check the following: plug, wire, and coil, if it is a random misfire code, start by checking your spark plugs(including the gap), plug wires, and coil packs.

P0171------ system too lean bank#1
Po174------ system too lean bank#2
For these 2 codes, try cleaning the maf sensor (mass air flow), that is mounted in the big black hose that goes from the air filter housing to the throttle plate, if it is dirty, that will cause those 02 sensors to send a signal to the computor to lean the air fuel mixture. If cleaning it doesn't work, the sensors will probably need changing.
P0300---- Random/multiple cylinder misfire
P0316---- Cylinder misfire at start up---- first 100 revolutions.
On those 2 codes, you have to do some testing to find out why there is a misfire.
Possible causes:
dirty/malfunctioning injectors
weak coil pack
fowling spark plugs/wires
Low fuel pressure

You will need to replace no 5 and no 6 coil pack and spark plugs. P0316 is random missfire that computer could not detect the cylinder that was causing it,just knew one was missfiring.
Coil packs are common concern on these vehicles. Can get oil leak into the coil pack wells and may also even get moisture into them.
If yours is a 3.9L it may be involved in owner satisfaction program 07M07 or 07N09 in which they will cover them under the program for up to 10yrs or 100000 miles which ever comes first.

Replace the coil pack.