It is my understanding that if you store gasoline for extended periods of time that you must add octane or something of that nature to the gasoline to keep it useable. Is this true for diesel fuel as well? If so does anyone know how long you can store diesel before it goes bad or becomes unusable? Thanks, Mike. 77'/87' 3/4 ton Burb, 400cu, sm465, np205, 14boltff, dana44, 4.10s, 35in BFG's.