where do you find 93 in portland. I've looked around and with the alcohol they are required to put in I've found nothing over 91.
although I've never heard any 'pinging' with the volvo, It says it requires 92 an I suspect that the computer retards the timing to alow for lower octane. ( It does seem to have a bit more power when I've been able to run a few tanks of 93 through it while working out of town)