these temp sensors are notorious for working good for years and also for NOT...the ecm is highly reliant on CTS input...you can easily check your CTS by unplugging the connector, reading the resistance with a $4 digital VOM and comparing to correct resistance as given in the FSM for your year...many are off calibration but not bad enough to throw a code, just enough off to mess up starting and gas mileage...most can be changed out without even draining the coolant from the car --remove the radiator cap to vent any pressure (NOT while the engine is HOT) and then reinstall the radiator cap, loosen the old CTS, have the new one right next to hole when you unscrew the old one and make the changeover with steady hand (do not try to be too fast -- that is when trouble will find you)...expect to loose maybe a half cup of coolant.
be careful not to let coolant run onto the lt1 opti distributer, might kill that...make a temp ''raincoat'' for the opti from a shop rag+ plastic bag while you play.
really can't complain about what these do for the $40 that they cost, tho...a similar type sensor for industrial use costs abt $200