I have a 2002 Chevy Trailblazer. Just replaced

Check the alternator for power output. Check the battery also. The 3000 to 4000 RPM is set at the factory so you don't blow the engine up.

If you can get it to run, take it to an o'Reilly's or another part house that tests batteries on the car - they do it for free. They can tell you what is wrong.

what exactly is the question ?

Low power lean conditions cracked air intake tube GM Testing by a qualified repair person with proper diagnostic tools is the way to a proper fix , not someone guessing !

It sounds like your EGR valve needs to be replaced. You can go to any auto parts store and get one. Try replacing spark plugs and plug wires also. If the timing was off it would pick up speed slowly and would vibrate really bad at idle. When you go to accelerate if it doesn't accelerate normally it may be the timing but i highly dought it. Try plugs and wires first. then the EGR valve.

check fuel pump pressure or clogged fuel filter

have autovone check the alternator

check throttlr sensor

try changing the air filter ,i had a problem ,at ilde in drive my trailblazer would stall, changed the air filter now it's not stalling and got my power back ,there is a secondary air pump that i have to change ,
not sure were it is ? still not running perfect but it's running better .and my service light is on too.
i got it put on scope ,it's the pump .
not sure if this helps ,but i'm start to run in to problems too,i have a 2004 trailblazer.
i like to do fix things myself ,i hope i can.it's the cost if you know what i mean.

sounds like fan clutch.