Codes P0118 and P0304, Idling rough?

Hello, we are honest here, no worries, this is a free service. The first code you're getting is for the Coolant Temperature sensor voltage too high (p0118). So, you may have a bad coolant temperature sensor, but also, there is somewhat of a refill procedure to make sure all the air is out of the system. There is an air bleed screw for when you are refilling the system. Do not open the system when it is hot. Only open it in the morning after it has had time to cool off. I'll post the instructions for bleeding the air out. But make sure there is enough coolant in the reserve/ overflow tank and only add to the tank when the engine is cold. Adding cold coolant to a hot engine can crack the engine block.
Have you noticed the temperature gauge is either too hot or too cold? The engine might be running rough if the coolant temperature sensor is giving inaccurate data to the engine computer. As well as the P0304 which is a cylinder 4 misfire code. I will post the coolant air bleeding process. But there might be a wiring issue with the coolant temperature sensor, it is a 0 to 5volt sensor, and this code is stating the voltage is higher than 5 volts for more than 3 seconds. So that points to the short to power on that sensor circuit. But replacing the sensor first is the easiest thing to do since they are not expensive, and some of this service information is mentioning just a bad sensor can cause this code, whereas other sections say being above 5volts sets the code. So, there are some variables there.
I'm not sure which engine size you have, there is a 4.0 and a 4.7liter, so the Coolant Temperature sensor location will differ depending on engine size, but the 4th diagram has the wire colors for the temp sensor.
As for the p0304, cylinder 4 misfire can be caused by a bad spark plug, spark plug wire, fuel injector, compression or valve issue. So, start with pulling out the spark plug and verify you have a strong spark at that plug. There's a couple of guides below to help.
I think once you get the temperature sensor issue straightened out and the coolant system bleeds completely out of air, you will notice a huge difference in performance. The coolant temperature sensor is one of the main inputs especially when the vehicle is cold. A faulty reading will skew the fuel strategy of the engine computer.

As a side note, there are a couple Technical Service Bulletins having to do with engine performance, One has to do with carbon build up on the intake and exhaust valves and the other 2 are for an engine computer (PCM) reprogramming, If you still have performance issues after replacing the coolant temperature sensor, you may want to see if the dealership will do any updating of the PCM since it has to do with engine misfires which you are having. The carbon issue on the valves will also cause cylinder misfire codes.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

https://www.2carpros.com/articles/how-to-check-for-ignition-spark

No problem, glad to help, if you have any questions and or want to test the coolant temperature sensor circuit, we can do this if you have a basic multimeter, a cheap $20.00 meter, will work. We are only reading up to 12volts dc. So, no need to worry about getting zapped or anything like that. Because of the difference I read in the code setting criteria, making sure that the coolant temperature sensor circuit is not shorted to ground or shorted to power would be a good idea. Also checking the charging system voltage while the vehicle is running can't hurt, because it looks like this vehicle has a battery temperature sensor as well. We can also do a couple of other really quick tests to make sure all the engine, body and battery Ground connections are okay. Super simple tests that can save you a ton of headaches in the future. If you want.