Misfire

Chevychic

Original poster
Member
Jul 30, 2021
1
Ohio
Help! Have a 2006 Chevy trailblazer. After getting atune up, it started misfiring. Got a diagnostic that it was cylinder #5. Changed out all coil packs with new, still having misfire issues with #5. Think the spark plug may be gapped wrong. Any suggestions?
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
What plugs did you use? This engine only like ACDelco 41-103 plugs.
 

rchalmers3

Member
Jul 11, 2020
207
Irmo, SC
When you investigate the gap on #5 plug, also check closely for a crack on the plug insulator. It's easy to damage a plug if you are trying to move quickly while laying on the radiator core support.

Also, pay attention to the coil connector condition: wires, pins and power supply.

Rick
 

Redbeard

Member
Jan 26, 2013
3,466
The ACDelco 41-103 plugs don't require "regapping" like older plugs I grew up with. If one tries to set the gap the irridium is easily damaged. Of all the irridium plugs I have checked the gap has been good. I have measured these with a dial caliper. aka don't try to use feeler gauges either. Again the irridium is easily damaged (which doesn't make sense since they easily go 100k miles if we don't push and prod the new plugs) If you see a gap it's ready to be installed on the engine.
 

JerryIrons

Member
Dec 20, 2011
434
Well if you changed the coil packs, I would be tempted to either swap out spark plugs with another to see if it's followed, or just put a new spark plug in.
 

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