oil pressure gauge

[gloreboy89]

ok now my problem may not be the exact same thing as his but I have a few of his problems and i maybe related. Ok, about 2 weeks ago i changed out the spark plug wires because the old ones was worn out(IE sparks was seen at random spots on the wire). After i put the new wires in everything seemed fine until when the car hit normal operating temp. then the oil gauge slowly went down and the battery level shot up to 17ish. I dont know why it did that because not even a month ago i change the oil. The only thing I know that is wrong electricity is that the battery terminal has some white chalk like material on it that i clean every so often.