Just switched to synthetic oil in my '95, 2.5 Lt this week and my oil pressure has gone nuts. It goes all the way to 6 and looks like it's trying to climb higher but the gauge only goes to 6... Any ideas? The oil has been changed religiously every 6000 KMs since new. When I let it idle, it drops back to 3, but as soon as I give it throttle, back up it goes... TIA