Definitely start with the connections as was noted ..and engine/body grounds. They're not difficult to loosen/wiggle and re-tighten and it's free. You might wiggle some wire connectors in the engine bay and check/reseat (wiggle) fuses in the fuse box. Have you checked any of the fuses. There've been a few guys who have remarked (in the past) some of their fuses had worked their way 'up' and they pushed them down.
What's the underside of your engine's oil filler cap look like? (milky? ..or normal?). You could possibly have two different things going on ..a misfire (coil/plug/headgasket/low compression?) and the CC issue. Perhaps if you pull into Autozone or OReilly's they can use a better scanner to tell you which cylinder was misfiring. Then you can target where the problem is. Inspect the connector to the coil for damage or corrosion. Then, remove the coil and check the plugs in the cylinder (or replace them) and ohm-out the coil. You can ohm out the plugs too ..check the porcelean for electrical trace cracks. Coils do fail. Even if everything measures out 'good' you can cross these common issues off the list. But if you're going to remove the coil/plug, I would rent a compression tester (beforehand) from the parts store (free to rent) and do a compression test while you have the spark plug/s out. If everything turns out 'good' then at least you know those aren't the problem and can look elsewhere.
Chances are the compression is fine ..but you never know. A burnt valve or failing head gasket can cause low compression. Might as well do good basic troubleshooting now to find out and know it's all ok, or you have problems to deal with now. I happen to have a vehicle (not the Ram) where I was getting a misfire last year. Turns out it has low compression in that cylinder. Not sure why, ..that particular engine does have a reputation of burning valves in the center cylinders. But then last winter it started using some coolant, the oil cap underside is 'milky' ..and the oil pressure is low now too. It's not leaking coolant, but the engine is 'sick' for lack of a better word. Obviously there's a 'rebuild' coming up here pretty soon for that engine.
But in your case it would be good to know those things and if you plan the process out right it won't be any more work if you do it all at once. You can youtube how to do a compression test and ohm out a coil/plugs.
