2000 Galant V6 Dies At Idle - But Only When Warm! Options

[ohfreak]

144k miles on this little fella.

Three days ago the battery finally gave out (after a couple months of it getting increasingly more difficult to start) so we popped a new one in. Started up and idled normally in park and in drive. Drove about 10 minutes (enough time for the engine to warm up) and came to a stop and the idle dropped off and the car died. Started right back up and died again. Able to keep it going by pressing the gas and keeping RPM above about 1000. Arrived at our destination and put it in park - died again.

Got back home and started again the next morning - again idles normally in park and in drive for a few minutes until the car gets warm, then dies. Same thing - when warm it will die either in drive or park, but not when ice cold.

The only thing that's changed is the new battery. What is going on? Possible that a vacuum hose was torn while changing out the battery? Any ideas?

Thanks in advance!