Dancing Temp Guage

I have a 99 Oldsmobile Silhouette Premiere Edition. My coolant temperature sensor seems to dance all around the place. It can go from the extreme right to the extreme left and back again within just a few minutes. The coolant level is full and does not seem to be leaking. Im thinking its the coolant temperature sensor or rad cap.

Has anyone else experienced this problem?

Thank you.

one of two things, you either have air in your cooling system, or a bad temp sender. The 3.4's are known for intake leaks, which allow air in the system. When the air passes the sensor, it pegs(because the sensor isn't submerged it coolant and shorts), then when the air bubble moves, it returns to normal. Try changing the sensor first, as a bad sensor will do the same thing. One last note, if you've recently changed the t-stat, the bleeding proceedure is a pain in the butt and air in the system is the more likely cause.