I just purchased a '91' Continental and the warning chime for the oil pressure keeps ringing. There is nothing wrong with the the oil pressure, the levels are ok, but every so often the chimes go off and the oil icon will flash and the bar graph will drop. Can't figure out why. Also the chimes will go off shortly after starting, say about a mile down the road and will continue for about a minute. Or just start ringing whenever, with nothing to tell me what the problem might be. Does anyone know about this problem?