P0404 code on my dodge please help

My car code P0404. Waiting for empty your gas tank and fill up with 93 high octane . Run one hour then code P0404 gone . One month two time fill with high octane .I don't see Code P0404 Try it . Good luck

REPLACE EGR VALVE ASSEM. THEY GIVE A BIT OF TROUBLE. CHECK FOR WARRANTY!! PRETTY SURE HAS EXTENDED WARRANTY FOR THIS.