Sorry in advance for the long thread. I bought this car in Dec 2005. Within a month of using 87 Octane, I had light spark knocking on acceleration , ususally arnd 1800rpm. I started using Chevron 89 Octane in the summer. It helped for a while, but then got worse. Took the car into tech, they allegedly put in a computer update. Didnt touch the problem. I then read the owners manual, I noticed it says (use octane greater then 86) , I also see the v6 has a compression ratio of 10:1....So I start using Chevron 93 Octane. Great acceleration, but at idle it brings the rpm to 650 (My car idles best at 700) After a few tanks, the knocking was all but gone...on occasional instances, I could still hear it. THe tech says "use 93, its a high compression engine" THe service writer says "You shouldnt have to use 93" I switched to Shell 93 3 tanks ago...I now have no knocks, but the car in my opinion (dont laug) seems to shift more often on acceleration...but no knocks.

So I have to bring the car in for service next week. Im debating wether to really keep after them about this, or accept that the car must have 93 OCtane. SOme cars, like my Nissan, the manual states that light spark knocking is actually a good thing. THe Honda Oddesy manual says use 93 if you are towing.

So whaat do you think?

Summary:

2005 Honda Accord V6

Hess 87 Bad Knocking

Shell, Chevron 87 Knocking

Chevron 89 some knocking (Overall , smoothest engine running and idling)

Chevron 93 Almost No knocking, Great acceleration, but engine sounds rougher and lower rpm at idle..(Im cheap, do I really have to buy this 93?) [:@]

Shell 93 No knocking , good Idling, engine sounds different and gears up differently.

Thats the story..I appreciate anything you can share before I go back for round 4.