04 trailblazer wont stay running

What's the voltage at the battery with the car running ? Testing an not guessing is the way to do proper diagnostic's ! Battery light staying on , is there B+ voltage at the alternator connection's ? A new alternator won't make a bit of difference if no power to the alternator . Looking at a wiring diagram an testing the electrical circuit ,doing voltage drop testing , plus checking for DTC'S - diagnostic trouble code's . Some vehicle's charging systems are computer controlled . And looking at a wiring diagram i see your vehicles charging system is computer controlled . If you have done so already , take it to the dealer

Battery Disconnect or Replacement Problems Probably need to do a throttle position relearn , you vehicle has electronic throttle control !

It can be low fuel pressure issue or clogged fuel pump.Or its engine related issues,---------------
Check the help link mentioned below to troubleshoot the problem :------

Engine stalls when gas is given?

http://technoanswers.blogspot.in/2012/01/engine-stalls-when-gas-is-given.html

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Car stalls when MAF sensor is connected?

http://technoanswers.blogspot.in/2012/01/car-stalls-when-maf-sensor-is-connected.html

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Car Engine Stalls While Driving?

http://schematicsdiagram.blogspot.com/2011/12/car-engine-stalls-while-driving.html

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Car stalls and throws white smoke from exhaust?

http://repairhelpcenter.blogspot.com/2012/01/car-stalls-and-throws-white-smoke-from.html

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Stalls And Dies At Stop Sign?

http://www.howtobyme.blogspot.com/2012/07/stalls-and-dies-at-stop-sign.html

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GMC Sonoma Stalls and idles low

http://technoanswers.blogspot.com/2012/10/gmc-sonoma-stalls-and-idles-low.html

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Nissan Pathfinder stalls and bucks on Acceleration?

http://technoanswers.blogspot.in/2012/02/nissan-pathfinder-stalls-and-bucks-on.html

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1992 Chevrolet stalls and shutdown?

http://schematicsdiagram.blogspot.in/2012/04/1992-chevrolet-stalls-and-shutdown.html

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Stumbling and stalling at idle after engine rebuild?

http://schematicsdiagram.blogspot.in/2012/03/stumbling-and-stalling-at-idle-after.html

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1990 mazda 323 stalls and quit running?

http://technoanswers.blogspot.in/2012/02/1990-mazda-323-stalls-and-quit-running.html

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2000 Toyota Camry: Idling and Stalling Problem?

http://whatisbyme.blogspot.in/2012/05/2000-toyota-camry-idling-and-stalling.html

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1995 Toyota Corolla: Stalls, Sputters and Pops Through Intake Manifold?

http://whatisbyme.blogspot.in/2012/05/1995-toyota-corolla-stalls-sputters-and.html

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1999 Toyota Camry: Erratic stalling and high engine RPM at idle?

http://whatisbyme.blogspot.in/2012/05/1999-toyota-camry-erratic-stalling-and.html

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Dodge Dakota stalls, stumbles at idle. Has low fuel flow and runs hot?

http://schematicsdiagram.blogspot.in/2012/03/dodge-dakota-stallsstumbles-at-idlehas.html

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1994 Toyota 4Runner: Stalls and Stops While Driving?

http://whatisbyme.blogspot.in/2012/05/1994-toyota-4runner-stalls-and-stops.html

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1997 Toyota Camry: Erratic Idle and Intermittent engine stalling?

http://technoanswers.blogspot.in/2012/04/1997-toyota-camry-erratic-idle-and.html

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Ford Maverick: No Idle and Stalling issues?

http://schematicsdiagram.blogspot.in/2012/04/ford-maverick-no-idle-and-stalling.html

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These details will help.
Thanks.

The battery light comes on when there is an issue with the charging system. Most likley you have a bad alternator. With the engine running you should see a min. of 13.5 volts at the battery and better yet 14+ volts. If you have 12.5 or less than the alternator is not charging.

Once the vehicle is started the battery is no longer in play. The alternator is what keeps the power supply to the vehicle and recharges the battery for the next time you want to start the vehicle. Once battery voltage drops below 9 volts or so systems start to shut down. Eventually the battery will drain enough that the engine management system can no longer function and the vehicle will stall.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

If the battery was dead after it stalled,then the alternator is not charging,check the alternator anyway,it needs to be charging for the engine to stay running.

make sure your idle air control motor is working, if you give and hold gas pedal a little will it stay running in drive.

i know this may sound stupid but if your battery is old or a little weak on this vehicle the idle air control solenoid will act speradicley hunting for were it should be and the vehicle will stall.replace battery

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.

check the Ignition Starter Switch (tipical on tb)

sounds like a fuel problem u need u check to make sure u getting fuel to your injectors but known how earlyfuel injectors are i would say theyre ur culprit here