I have a 2003 Dodge Ram 1500 4x4 5.7 Hemi.

Yesterday it started misfiring and having an incredibly rough idle. I have a suspicion one of my tenants put sugar in my gas tank as revenge. However I would like to check a few other parts before I drop the tank.

What else do I need to look at?

Also there’s no codes.

 

There are videos for testing fuel injectors. You listen for a fast clicking sound using either a mechanic's stethoscope or a long screwdriver.
Make sure the injectors are all clicking and we can go from there.
Sugar in gas tank is usually not an engine killer.

 

Could be something going on with one or more of your valves, or coil pack failure. Such issues usually generate a code though. To test them. Run engine and unplug coil packs one by one. Each one you unplug should make the engine run worse. The one that doesn't, is your culprit.