Unfortunately it seems like manufacturers put gauges in the car to make it look technical, and that the consumers hardly look at their gauges which is why we have switched mainly to idiot lights. If you want race track accuracy, you are going to have to go with aftermarket gauges. The stock ones just don't seem to cut it. My friend's old Cavalier and just about every other one I have seen (was in the early 1990's models) has their oil pressure gauge pegged when the car is started, and under idle sits in the middle quivering. My Camaro's gas gauge starts to fall off after 1/2 tank because apparently the gas tank is not a simple square shape, so by the time the gauge reads 1/2, it is actually only about 1/3rd. I think that this might be the case for the Contour as well because my gauge did the same thing. At least 200 miles to the 1/2 mark, and then steadily to E over the next 100 miles if I pushed it.
