2013 Honda Civic

The owners Manuel says to use 87 octane. I've been using 86. Will this cause damage to my engine? Does the octane rating really matter in this situation? Does it matter what gas station I go to i.E. Costco, chevron, am pm, etc. Do they really sell cheap gasoline to consumers? Thank you for your help.
June 15, 2013.

One octane point you should be OK. As far gas it matters for fuel efficiency keeping the injectors clean etc. Chevron Texaco 76 Philips 66 shell etc are good top tier fuels.

Jun 15, 2013.