I noticed in hot weather regardless of what therm. I had the car ran like a dog....LS1's reacted to heat much better but still ran crappy

 

Mine used to run around a quarter of the way when moving and around 210 when sitting. Recently my low coolant light comes on all the time ,but im full of coolant and im running 210 while driving and almost peg the red when sitting. I think i may just need to flush my radiator.