My 2002 V6 DX stalled last nignt. It started with a boost but died when I took the cables off. I replaced the battery today and it ran great for about an hour and I had the same trouble again.

When the battery starts to run low the acceleration begins to fail. After 15-20 minutes the machine will start again and run for about 10 minutes.

Anyone know what this might be?

Sounds like your alternator croaked. If it dies, there is nothing to recharge the battery. Hence the battery drains to nothing.

Pull the alternator and have it tested.

Definitely sounds like an alternator failure or connection problem between the alternator and battery. Will run ok after charge because the engine is running off of the battery instead of alternator output. As the battery becomes more discharged it will start running worse and worse untill stall due to loss of available voltage to run the ignition system and injectors.

As a point of information, I discovered that the alternator needed to be replaced.