Troubleshooting for 3rd Cylinder Misfire

[Bugeaters36]

So I had a few after market parts installed on my 2015 Silverado: Flowmaster 40 series, Volant cai and finally some Gibson performance headers (heat wrapped and all). I didn't have any issues until the headers were installed. Shortly after leaving the shop my truck isn't shifting correctly and my engine light is on. I figured over heating was the culprit and that I should let it cool down before taking it back out for some fun. Hours later the problem is persistent and my truck is down shifting at too high of rpms causing it to jerk and stall for a second. I also feel like there's some power loss. I plugged in my Diablo inTune i2 and it showed the error code being a 3rd cylinder misfire and rough idle. I checked all of the spark plugs, the wires and all the bolts but I can't see an issue with any of them; all the plugs tested good and all the bolts are secured.

 

Does anyone have any insight as to what the problem could be?

[Dnt]

Probably a damaged plug wire from all the underhood activity. Just replace the plug wire on #3 and you should be good to go. It happens man not a big deal, no need to beat up on the guys that installed the headers they probably did the best that they could.

[Bugeaters36]

Would the plug tester still work if it were the plug wire? 

 

I'm not upset with the installer at all, really good guy, I just want to get my baby running right again. 

[Dnt]

you might actually have a cracked ceramic on #3  spark plug. Go ahead and replace the plug and plug wire for 100% coverage and no wasted time.  

[Bugeaters36]

Lesson learned buddy! Although the spark plugs tester was giving me the ok, I went ahead and pulled it out as recommended and bam. Totally burnt up. Replaced it and now it's running beautifully. Really appreciate it man, thank you!

[Bugeaters36]