HELP furnace short cycling!

replaced or checked all I can think of ?! calls for heat, inducer starts, flame rod glows, flames light, then goes out..repeat.
**just replaced flame sensor, pressure switch, inducer motor, still going out?!**

New gas valve, just a month or so ago

New heat exchanger, flame rod and control board last year.

we replace every part as needed. what am I missing now??!!