Why won't my 2002 Mercury Mountaineer do a warm start?

My 2002 Mountaineer has been in storage for the summer. Last week, I charged the battery to take it out. The battery tests out fine. If I do a cold start of the car, it starts normally 100% of the time. If I drive long enough to warm the engine, shut it off, and restart is a moment or two later (long enough to fill it up with fuel), the restart is difficult. I will start, but the engine will rev, almost cut out, rev almost cut out. It will do this a few times before finally stabilizing and running normally. Is this in relation to the fact that it has been shut down for the summer? If so, what is causing this and what can I do to fix it? I appreciate your thoughts in advance.