My chaeck engine light comes on and off. Says number 6 cylinder is miss firing.

What is your question?

I ran seafoam through it in the gas tank and beat on it for a few days and the light went off for a week then came on again. Should I be putting in 91 octane? Will that help. The dealer put in new plugs and a coil and ran cleaner through the fuel injectors. then the light came on 2 months later. They say, they would need to take the top end apart and clean it good for $1000. Isn't there something else I could do?