I owe a Sprint ST 955i since last summer (when I replaced my Sprint 900 Executive). Last week I filled it up with 98 oct. in stead of the 95 oct. And since then it is behaving strangely. It stalls when driving at low speeds, and my speedometer and tacho needles are going crazy, jumping up and down, the digital tripmeter quits... a lot of electronic hick-ups. Could this be related to the fuel quality and will this pass after fueling up with 95 for a couple of times, or should I get worried ?