Bad Fuel Injector Symptoms?

2015 Jeep Grand Cherokee with the 3.6 Pentastar in family but diagnosis from afar... Low on gas (15 miles to empty) then abrupt misfire with flashing CEL, limped to gas station, filled, limped home. Scan tool had misfire on cyclinder 4. Reset the computer with battery disconnect. Ran fine for a week plus. Misfire returned. Plugs and coil packs replaced on all six cylinders (Non-Mopar, bought parts on Amazon). Fuel injector cleaner bottle dumped in gas tank. Reset again and ran fine for another week or so. Misfire is back and scanner says cylinder 4.

Next thought is a bad fuel injector, right? Of course cylinder 4 is under the PITA intake plenum so if swapping injectors to check is a pain. Am I missing anything else? 
 

Thanks!

Before you muck with injectors, might just replace the fuel filter...

I always try to clean them manually first.  Jump the fuse so they run when pulled from the manifold and engine is off, if it squirts like a squirt gun get out the tooth brush.  Keep cleaning until you get an atomized mist.

May want to do a compression test and a leek down test on that cylinder.   
 

I have "fixed" poor injectors by running the fuel very low in the tank and then putting six bottles of the Chevron Teton injector cleaner in the tank. Drive it around a little to mix it in the tank and to make sure the now treated fuel gets to the entire fuel system.  Park over night and then start for a couple minute and let set again.  Then fill with premium fuel from a brand name station. I like the Shell 93 for this as it seems to have a really good additive package. Run a couple tanks of this and see if it then helps things.    This has un stuck a couple injectors for me in the past and generally improve the smoothness of the motors.  

The only car I had with an injector failure, the injector just quit working. A noid light confirmed it was getting a signal, just no clickely anymore. A long screwdriver worked to listen to the injectors and confirm it wasn't clicking anymore.

In reply to Old_Town :

You getting bad gas?  If you have a lot of moisture (water) when level gets low you will get really poor performance.  
 

I'd be tempted to get a fuel sample when low.

The tell tale sign of bad gas is a slow filling pump at a gas station.  That means fuel level is low and water chances are higher.  Also gas stations with low traffic are worse in this situation.  The busy ones get fuel so often water doesn't get a chance to build up.

If the pump is slow, I usually get a few gallons and fill up elsewhere.  

Thanks all - Makes sense. Apparently the fuel filter for these is an in-tank 'extended service life' unit that 'shouldn't' need any changing but good idea. The moisture in gas is interesting, I'll have to attack that further.   

Also let whoever in the family ran it that low know that the in-tank pump uses the gas to cool the pump & also when there is very little gas in the tank all the in tank crud is concentrated at the filter. 
When our son was young he would run cars low. After 2 fuel pumps in 2 cars he finally listened.