Check your oil. Don't wait for the change to find out your low. If it's low and that's what is causing it you could be causing damage to your motor every time that light comes on no matter what your oil pressure gauge is doing. The gauge is designed to slowly sweep to position so that it looks smooth and not jittery as it would really look if it truely represented your oil pressure. And your motor is designed to specifically work with a certain amount of oil. The less oil there is the more the contaminants in the oil are concentrated, the hotter the oil gets, the more the oil breaks down and the more sludge is created. If you ever think your low, check it right away because contaminated, hot, broken down oil full of sludge doesn't lubricate well... especially when there isn't even enough for the pickup tube to scavenge off the bottom of the pan.
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