what causes air in the gas line WITH a valve on the engine? how to fix it? on 1999 Chrysler Town & Country

since its been so hot,van will start running bad n cut off,we found out to make it run again,is let air out of the valve on the gas line on top of the engine,does anyone know what causes this? and/or how to fix it?it happened 4 times yesterday,on the way home

Asked by for the 1999 Chrysler Town & Country
FOR SAFETY SAKE bring it to a dealer, explain what you've needed to do and ask if there are any service bulletins relating to this issue ---not necessarily recall or warranty --just a known issue and repair.Nissan had an issue with their early Maximas that match your description of symptoms.