Idling problems
 

I have a 2000 chevy Z71 and I am having idling problems. It runs fine when it's still cold but after it gets warm it idles down past 500 rpms, I have changed the IAC sensor and nothing different. I changed the fuel filter and the same results. I checked all around the intake for air leaks and haven't found any. A buddy told me the cataylitic converters may be stopped up. I don't want to start swapping things out spending a bunch of money. Any help would be appreciated

Re: Idling problems
 

You should start off with the basics.
have it scanned for codes and a look at vacumn, fuel trim, etc.
check fuel pressure
a good muffler shop can test the back pressure before the cats to help rule out a plugged up cat or muffler simply by removing the o2 sensor and inserting a pressure sensor. If there's blockage the truck will be down on power especially under wot.
a vacumn leak can be down under the intake manifold runners making it hard to locate. and these composite manifolds are prone to cracks.