Let's talk about a misfire [code]

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Derick

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Ok, so my truck was at the mechanic (trusted) for the replacement of the front diff. As usual, I told him to look around and make things right that he felt might not be. Because of some not-so-great work done somewhat recently at a local muffler joint, nothing would surprise me.

Front diff went in, everything related to that seems fine-ish.

He did call me and have a few small items to tend to, and they are as follows;
-Replacing the coolant temp sensor, it had clearly been broken by someone not being careful (surprisingly, not me)
-A few of the spark plug wires were missing their heat shields
-Cleaning up the mess of wires on the drivers side and putting the harnesses back where they belong
I feel all these items were a result of the morons at the muffler joint, I'll never do business there again and will spread the word accordingly. One of these wires that he would have disconnected to put on a heat shield was indeed cylinder 6, so I figured a loose wire, and an honest mistake. No such luck, nothing seemed loose at all.

I am now getting a misfire code that I never had before. It throws a flashing engine light, and starts shifting hard into 3 and/or 4. Sometimes the light will clear itself, sometimes it wont. When I first experienced this, I was getting a P0306. Cylinder 6 misfire. I replaced the coil pack, no change. Mechanic said to try replacing the plug wire, so I swapped it with cylinder 2. While I get the same behavior, I am getting a different code. P0300 which is saying generic/multiple cylinder misfire.

I've never had engine codes before, and I dont think the mechanic changed enough stuff to really throw things off. Motor is running as I feel it normally does. It's not rough or anything, has the usual get up and go I'm used to. But I'll be honest, I've been driving this thing hard lately, lots of pedal into it...and this is the first time this stuff has happened. The plugs and wires were changed in 2019 sometime, less than 2 years old.
 
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Derick

Derick

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Well the code changed from p0306 to p0300 when I moved the plug wire up from 6 to 2........to me, it doesnt seem that the wires should be bad this soon after installing them, but changing the criteria did change the resulting code. Why it didnt give me a p0302, I dont know, but I'm still researching here.
 

iamdub

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Did you clear the P0306 when you swapped the ignition wire around? What brand wires are they?

Cleaned the MAF lately or ever?
 
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Derick

Derick

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I Want to say they are the duralast gold ones....been a minute since I got them. The MAF is brand new factory delco from a different debacle that I created after the truck came back from a trans rebuild.
 

iamdub

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I Want to say they are the duralast gold ones....been a minute since I got them. The MAF is brand new factory delco from a different debacle that I created after the truck came back from a trans rebuild.

New Duralast anything has a pretty good chance at being worse than old OEM. I wouldn't be surprised if the wires broke internally when they were removing them. I'm assuming the exhaust shop replaced the manifold(s) or the gaskets?
 
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Derick

Derick

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New Duralast anything has a pretty good chance at being worse than old OEM. I wouldn't be surprised if the wires broke internally when they were removing them. I'm assuming the exhaust shop replaced the manifold(s) or the gaskets?
Correct and they ****** up a bunch of stuff in the process. I was thinking they have broken in all the rigamarow of all the yeahoos including myself monkeying with em.
 

iamdub

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Correct and they ****** up a bunch of stuff in the process. I was thinking they have broken in all the rigamarow of all the yeahoos including myself monkeying with em.

I'd hate to suggest throwing parts at it. But, with Autozone's house brand's reputation and considering they've likely been abused, I'd replace them even just proactively.
 
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Derick

Derick

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Got a set of ngks to pick up tomorrow morning. Definitely looks like a good likelihood that the wire is the culprit. That questionable wire that was on 6, is on 2 now and no other cylinders are reporting misfires.

Screenshot_20201007-172102_600x1277.jpg
 

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