Hard starting rough idoling and power loss

i would start by replacing the fuel filter.

run fault codes to find which sensor is not correct

try the fuel presure regulater it should be on the fuel rail ( that is if it is the V-6 ) it hasone vacum line on it and it has i think like 6 screws holding it in. it will cause just that same problem it will also cause it to flood at idle and foul plugs and make it idle rough you may have to chage the plugs also. you might check the vacum to. it should run on stright vacum from the intake.

Pull vac. hose to fuel pressure regulator . If fuel leaks out that is your problem.

Yes,sparkplugs could be bad.Also check sparkplug wires.If they havnt been changed in around 60.000 miles, chang them.

048 Engine Hard to Start or No Start Scan Data for Starting Problems This is how you find problems like your's , viewing scan data , sensor data parameters . What are the fuel trims at ? +- 5 to 10 % . short an long term trims . Do you know what these are ? Are the O2 sensors switch normally ? What's the coolant temp ? Intake air temp . Is the check engine light on or flashing ? Mass air flow sensor data . Misfire codes ?
047 Engine Hard to Start or No Start Scan Data for Ignition
056 Engine Hard to Start or No Start Misfire Scan Data

The catalitic converter is cloged up. Replace it with a "High Flow" type. My 2001 cloged at only 44000 miles.

White smoke means water getting into cylinders. Usually leaking head gasket, or possible intake manifold gasket if the manifold is heated with water! You need to see your service people again. Weather conditions should never cause this problem. The oil leak might be fixed by tightening all of the perimeter bolts on the oil pan.

check fuel filter then check the ignition system

Check the dodge website for recalls and see if the pcm needs to be updated. The pcm controls everything in that van.