So my folks went out of town for the weekend and took mom's 99 Accord. After being on the highway for 4+ hours they were in town and while stopped at a traffic light the car stalled. It started back up again but in order to keep it running while stopped it has to be in neutral and revving the engine. This has happened once before, recently, and under the same conditions - after being out on the highway for an extended period and then stopped in traffic. They stopped and parked the car for a while, once it cooled down a bit it ran fine, no stalling. Mom recently had the timing belt, seals, water pump, etc replaced; this problem started after that work was done.
Any ideas what could be causing this? Seems to only happen when the engine is warm and has been running for extended periods. Mom and dad are a little worried that they will be stuck out of town if its something serious.