4.8l Hesitating, Any Ideas?

[MDelgado]

Hey guys, you helped me a ton with my tahoe, so I was wondering if you could diagnose my other GM 4.8L in my 2000 Caddy. Right now, she'll start up fine, but will idle pretty rough. It will idle at around 600 and then 10 seconds later it will jump to 800. It's goes back and forth like this. At speed it will hesitate and lose power momentarily, but come right back. It only has 90k on it, so I can't imagine anything to be real worn out on it. Any ideas? The only thing I did was trace every vacuum line and check for leaks.

[Stevens03]

Check your throttle blade.. they tend to get alot of "coking" and will cause strange idle problems. And don't they have a 4.6L