i had an oil change about a week ago and until today things have been good. While driving to work, i was at a stop light and i received a "Low Oil Pressure. Stop Engine" warning plus the oil light came on. As soon as i started driving again the warning and light went away but kept coming on at each stop light/sign. Any ideas on what to check for? I have a 2004 SRX with a 4.6L v8 Northstar engine.