I have a 2000 new body tahoe with a 5.3 v8. when it gets warmed up and i stop and let it idle i hear like a ticking sound. someone said it could be a bad valve or lifter. any sugestions

Sounds like a lifter or the AC coming on and off.

check your belt tensioner, if the bearing is going it can sound just like a ticking lifter. i just did one on a 96 yukon and the ticking noise is gone.