Tomato plant wilts, gets better, and then wilts again.
Tomato Plants Wilting, Then Get Better, Then Wilt Again
I think this article may hit the proverbial nail on the head, for you: http://jacksonville.com/entertainment/home-and-garden/2010-06-25/story/gardening-nematodes-cause-variety-problems
Previous to the wilting we experienced 6 inches of rain in two days. I watered prior to that fairly heavily every other day, also watered with Miracle Grow for Tomatoes. I live in Central Florida and daytime temps are now in the 80's.
The problem started a few days ago. What is really strange is that the plants will look fine in the morning, then wilt and then may look fine again all in the same day. The plants are about four feet tall and have at least six hours of sunlight.
Expand your statement,. Are you watering, if so, how much, how often? How big are the plants? What are your daytime temps averaging? How long has this been happening?