My blazer starts out fine when cold,then gradually runs worse and worse. Pushing gas pedal to floor makes it worse. Finally, it will only run just above idle. I was able to limp it home Christmas eve. Does this sound like a bad EGR valve? When blazer sits it will start up again fine. I had intake removed and channels all cleaned, but not sure about EGR valve. I just took EGR valve off the blazer. The "torx" screw underneath is freely moving in and out when i depress it. Does this mean EGR is ok? or can it be faulty internally?

OK, I took the EGR valve off the engine, got a new gasket, cleaned all the carbon from the internal that I could see. The EGR plunger is free. I re-installed the valve. The Blazer starts fine as always. When I took it out to road test, I noticed the warmer the engine got the worse it ran. I barely limped it back home. I had only gone perhaps a mile from the house. It will sit and idle fine, but stumbles/bogs when giving much over idle pedal pressure. Is this an EGR problem, or perhaps, something else? I have replaced all plugs/wires. Fuel pressure is perfect. New air cleaner. New inline fuel filter.:icon_shrug: Any thoughts?

It sounds more like a clogged catalytic converter to me. You could pull the O2 sensor directly ahead of the catalytic converter to diagnose. This will relieve exhaust pressure and should restore performance if that is the problem.