wont stay running...again

Sometimes it happens that when a car is in nuetral, or park, that the rpm increases, and the advance springs in the distributor open, and the additional advance allows the engine to idle...when you put the car in gear, all of the advance drops off, and the engine stalls...check to make sure the timing isnt dropping off when you put the car in gear....the remedy is a little bit stiffer springs on the advance weights.