I have a heil model # eac3048sa1 867.80756 style#eac48a that is short cycleing the flame... it starts like normal and a few minutes after the main blower comes on the flame goes out for 15 seconds then relights and burns for about 45 seconds and then repeats the cycle the whold time until thermostat setting is reached... what do I have going on

By your description, it sounds like the high limit may be opening. Check all supply & return registers to be sure they are not blocked or otherwise restricted. Also make sure the air filter is clean. Do not use those high dollar pleated filters.