Maybe slight engine pinging as boost comes on?
Yes. That is 'premium' in California.Doesn't California have 91 octane?
Historically, Volvos turbo engines have been picky about the plugs. A common postThe one thing that perplexes me, is the wait for a recall to change spark plugs. Is the spark plug in this engine something unique, that an off the shelf one wouldn't be able to address?