Looking for help with this Volvo XC70 no start problem

Have a 1998 volvo cross cross country AWD. It ran terrific when we parked at 10pm then wouldn't start at 7am. Can hear fuel pump working and getting fuel to the injectors. Have seemingly good spark from coil to distributor cap then the spark gets very weak going into the plug wires. Any help would be greatly appreciated. Spark is jumping 2 inches plus checking it at end of coil wire then soon as i snap it onto the distributor it appears to die. Its very weak to non exsistant through all 5 plug wires so stumped as to what would cause the spark to die like that coming out of the distributor cap?? Any ody know what would cause this??