Car won;t stay running

You know all the spark plugs didn't fail at once and start working after the engine cools down so that was a waste of money unless they were due to be replaced anyway. The most common cause of stalling while driving is a failing camshaft position sensor or crankshaft position sensor. They often fail by becoming heat-sensitive, then work again when they cool down. Since you didn't list which engine you have I can't tell you which is the most likely suspect. Most of the time the Engine Computer will set a diagnostic fault code indicating which circuit has the problem. Did you read the codes? If so, what are the numbers?

When the engine doesn't start, did you check for spark?

You're not giving me any information I can use. Did you get fault codes for those misfiring cylinders? I have to guess you have a V-6 engine. Is it the 2.5L? Has the engine stalled again? If it does, check for spark before it cools down. Did the Check Engine light turn on while driving? It should when you get misfire codes.

You might want to check the fuel pressure when the problem acts up. This is not how Chrysler fuel pumps normally fail but low pressure can cause intermittent misfires on various cylinders and it can cause stalling. If the engine tends to stall when you start coasting at highway speed, you might suspect a plugged or collapsing pickup screen in the gas tank.