I have a 1990 PontiacGrand Prix LE 3.1 liter, (btw, this is a Canadian car, if that matters) recently I've noticed upon starting the vehicle, the oil pressure guage rises to it's maximum (I think it's 500-700 kpa). After approximately 10 minutes of driving, the needle settles somewhat around 250 kpa. I'm using the recommended 5W-30 oil, and as far as I can see I have no visible oil leakage. Question 1). Is it normal for the guage to fluctuate while accelerating? Question 2). And why does the guage start off so high upon initial startup?
Thanks in advance