I had a 160 t-stat installed yesterday. The low coolant light is staying on now. The coolant level is actually a little high, it's almost up to the hot line when cold. I can't see any sign of leakage. anyone have any ideas?

Bad sensor?

Did you Burp it? But ya you could have a bad sensor. You could pull it out and clean it off and see if that works.

Yesterday i raced a Turbo 240sx coupe and when i floored it the low coolant light came on but it didnt come back on when i raced a GT mustange the next day? Whats up with that

It could just be stuck. I had that problem on my car when the coolant was low, whether it was my old GA or GP, I can't recall. After topping off coolant, it was still reading low. But taping on the coolant reservior solved it and it went back out. What is it, a simple float bobber?

please go into details about the 240sx race!

No the coolant sensor appears to be some kind of electrical probe (conductivity/resistivity) measurement.