engine temperature guage on 1997 Lexus ES300

While the car idles, the temperature gauge goes way up, to the point of indicating overheating although I have yet to see it overheat. As soon as I start driving, the gauge returns to the "middle/normal" range. Any ideas?

Asked by for the 1997 Lexus ES300
check fan relays and fuse underhood
Thank you, and I will. Do you know where those might be located on the 97 model? I just bought the car the other day and I am not yet that familiar with the electronics.
1 more answer
Clean, and straighten the condenser fins located in front of the radiator, but be careful to not damage the condenser tubes. The air conditioning will work much better afterwards also! It took me about eight hours, over a three day period to straighten out the damage caused by bugs, and debris hitting the condenser. I also had to tilt the radiator toward the engine, and clean bird feathers from the radiator. Afterward, use a strong flashlight to shine through the front condenser and look for the light coming out on the engine side. Good luck!