First, have you checked that the exposure compensation is not accidentally set to +1? Second, have you tested the meter either against another camera body that is known to be accurate, or a hand-held meter known to be accurate? That would tell you how much the meter is off by, and if the problem is somewhere in the camera electronics (ie is the meter telling you correct numbers but still overexposing, or is it showing you +1 stop). Just being responsive to light isn't a good enough indicator - I have a 60 year old Rolleiflex whose internal meter is still responsive, but about all I trust it to do is confirm that Sunny 16 applies. Anything much more than a couple stops off noontime full sun and I'm breaking out my handheld.