Code p306 Chrysler 3.8 Engine, Help

There is an issue with one bank of pistons, 4, 5 & 6.
Probably an injector issue.
Always fit OEM parts.

Link to a reasonable explanation of the code and suggestion of checks below...

https://www.obd-codes.com/p0306

Your code it for a low battery voltage, your miss I would think might be a gummed up injector. Todays fuel does not store for long before it starts to varnish up. I suggest running some good fuel additive like B&G 44K with a tank of premium octane fuel and see if she clears out.

the problem will be in the unit that is attached to the end of the cam shaft that is driven by the timing belt/chain. It is hydraulically controlled by a solenoid that gets the signal from the ECM. Replacement of the unit by an accredited specialist will be the fix.
The unit changes the valve timing by advancing or retarding the cam shaft in accordance to engine RPM

yes if you have got a good spark then a faulty injector could be the problem , swop the injector with another and see if problem moves to that cylinder if not you know that its not the injector, i'd then try a fuel additive to clear any carbon deposits that would have built up over the years let me know how you get on

Defective or clogged fuel injector.

change out the plugs and wires then see how it runs....

Plugs...are cheap! Try that First.

Which engine?????? Check fuel pressure while the problem is occuring, this problem sounds like low pressure. It should be 45-50 psi

A P0306 code means that the the ECM has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #6.

A code P0306 may mean that one or more of the following has happened:
Faulty spark plug or wire, Faulty coil (pack), Faulty fuel injector, Burned exhaust Valve, Poor compression, and Defective computer. 

Check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the Caravan, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). The number six cylinder is the one towards the radiator and drivers side. If you are going to change all the plugs and wire keep me posted, be glad to help. Good luck and hope this helps, P0300 just means multi miss fire.