I noticed two things today with my car that concern me. I am hoping it is nothing, but I don't know much about car repair. First, I noticed that when sitting a stop light or idling the temp gauge will occasionally spike and then drop down to normal once I start moving. Initially I figured something was up with the radiator or fans and the natural air flow during driving was cooling it back down. However, I barely even have to move at all before the needle instantly moves back down. There has to be very minimal air flow and even that air is 80 degrees right now. Also, once I parked in my driveway I left the car running and looked under the hood. Both fans were working as normal. Second, when this temp gauge spike happens, the driver's side fan stays on for about 3 or 4 minutes after I shut the car off. The passenger side fan shuts off instantly. Could this just be a bad temp sensor or am I facing worse? Still under warranty but I just hate the hassle of getting repairs and a loaner, etc. Thanks in advance, Grease Monkeys.