messed with it for a while today. Filled it up with 93 octane. 1 thing i found was the vacuum dash pot that holds the secondary air door closed until the right time was blown out, so replaced it with a good one. Seemed to help a little bit. Then i tightened the secondary air door and seemed to help a small bit more, then limited the secondary air door a little more and it seemed to help a small bit, but all in all it still there some, just not as bad.