85 octane gas? coming across Nebraska yesterday I put 85 octane gas in my accord. it was only 10 percent ethanol. ( i now know the manual calls for 87 or higher) after 200 miles and when accelerating to pass, the car gave me the check engine light and dropped to limp home mode. i turned if off and it reset to normal. we drove another 500 miles home with no more events. I did put in a bottle of lucas injector cleaner and then the best gas i could get for two tanks. I have read too much on this site about head gasket issues. i do have the 1.5 turbo. Car seems fine now. I am inclined to blame it on my poor choice of fuel. Would you test for a head gasket issue? and if so , what test would you use? Oil and anti freeze look clean and levels are fine. THANKS !