To add to the information, since this started, I have changed all spark plugs and wires, and also, put in a new PCV valve. As you can see, I've looked into some of the cheaper possibilities.
How would one be able to check something like fuel pressure when something only happens when driving? It's certainly not something that happens while idling. I had read that it could possibly be a bad fuel filter or fuel pump, which is another thing I'm considering.
Thanks for all input.