How to fix Trailblazer that has a dead miss - 2007 Chevrolet Trailblazer

need more 411

you can use the scanner/computer for easy diagnostic and fix it.
this code engine missing fire, see the diagram

Try moving the coil pack from cylinder 1 to another cylinder (swap locations) and see if the same code comes up. If code is different, then coil pack is bad. Other reasons for miss; bad injector, poor compression.
Also, I know you changed plugs already, but always use AC Delco 43-103 plugs on this vehicle.

Although batterys range in price . The fuse box is located on the side of the dash when you open the drivers side .

Need more info......does it do this while the Defroster or A/C is on only? Meaning, with the Defroster and A/C OFF, and the fan on, it runs normal right? Did you recently disconnect the battery for any reason? Get back to me, I can help. Sounding like an easy fix here so far...

did you replace only one spark plug? that can cause issues because of differences in resistances between cylinders. also, did the map code stay off after replacing
?

ign coil

This is a pretty common issue for Trailblazers to have. Here's a link with more information about these GM gauge problems. And where you can purchase replacement parts on Amazon if you want to do the repair yourself.
Trailblazer Speedometer

Timing chain usually does not cause a miss. It may run sluggish or even backfire, but a miss is like a spark plug with the wire off. Like a dead cylinder. Chevy timing chains do stretch but those engines can handle quite abit of timing. I had one with 120K miles and it was only off 4 degrees. That's nothing for chevy to handle. A tune up is usually nothing but a set of plugs and a hook up to a diagnostic machine. I would look deeper. Go out at night, start the engine with the hood open. Make sure you are in a very dark place. Look for sparks jumping from plug wire. Another way to to use a spray bottle of water. Spray a very fine mist of water around the wires. If they are bad, a spark will jump. Check cap for deposits. You can only hope that the plugs were gapped right.
Good luck

a clogged fuel injector will cause a miss but no engine damage,