Replaced the spark plugs in a 2003 chevrolet trailblazer and it keeps dying

Alternator needs replacement

I’m happy to help further over the phone at https://www.6ya.com/expert/randy_4eae0e2ee1bfc3a6

starter bendix is out and needs to be replaced

Cylinder #1 misfire. If the engine is running fine the code will reset on it's own after 40 cycles of the ignition key. If the engine is running poorly it could be due to bad spark plug or coil pack.

try replacing or cleaning the injectors
when misfiring moves around it is seldom the coils , plugs and any thing else connected to spark but dirty fuel, low fuel pressure and dirty injectors or injector control
use a quality injector cleaner for a few tankfills

Hello maasdnl,

The firing order is 1,5,3,6,4,2 see image below for cylinder orientation.



I hope this helps.

Regards,

Jerry

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They are mounted down in the head, underneath each coil pack. You'll need to remove the top engine cover to gain access to them.

CHANGING SPARK PLUGS IN TRAIL BLAZER. YOU NEED TO REMOVE AIR INTAKE RESONATOR AND IGNITION COILS.YOU NEED LONG 3/8 EXTENSION - SPARK PLUG SOCKET - 3/8 RATCHET WRENCH. NEED SPARK PLUG GAUGE AND A TORQUE WRENCH.YOU CAN GET BY WITH OUT ONE LONG AS YOU DONT OVER TIGHTEN PLUGS AND STRIP OUT ALUMINUM THREADS.

this is more common on high mileage cars. you should probably replace all the coils as it's common for them to go bad on this model car

ON TOP of Engine there 6 Coil Units the SPARK PLUGS are under them, and they Require a 10mm Socket or Wrench to remove them, once the BOLT is out PULL OFF the COIL and there is a Rubber BOOT that ALSO Requires Replacment Along With The Spark Plugs.
the Spark Plugs are DOWN INSIDE the HOLE.