# P0300 code, CoilPack?



## unitednations161 (Mar 13, 2011)

My 2011 Cruze eco was starting to have slight blowout, due probably to the plugs being over gapped, i have the coppers in. So i took them out and regapped them. back to .028
Well after that driving the car it began to really misfire, I mean like a rodeo bucking bronco. I did notice one of the coil boot is ripped but way up top where it slides over the plastic. I went and bought new plugs, tried that and for the first day it was fine, then the second night driving to work it did it again. It doesn't just feel like blowout from over gapped plugs, it feels like it goes into a strange mode and the CEL flashes and what not, Now I'm getting a P0300 code.


I do have the coil pack off now, and I do see green corrosion where there springs meet the pack. Im waiting for my new coil pack to come, to see if that was it. Im just wondering how in the world did just taking it off and regapping/changing the plugs make the coil pack act bad? If that is it anyways.


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## Dngrsone (Jul 3, 2017)

I'm thinking that the tear in the insulation was the main problem. Moisture getting in there and creating corrosion could cause problems.


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## JRB'sOilburningCruze (Feb 25, 2015)

P0300 is random misfire. If it was one cylinder you'd get a misfire code specific to the cylinder. Such as P0302, etc.

I hope the coil pack fixes it for you. If it does not, you need to go a proper trouble shoot procedure or you'll just end up throwing parts at it.


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## mechguy78 (Jun 6, 2016)

I'll agree on the proper troubleshoot as the P0300 is the hardest misfire code to track down.


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## unitednations161 (Mar 13, 2011)

So i got my new coil pack, day one seems ok. It did stall on the cold start but these cars have issues starting when a temp change over night. Anyone else notice this?


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## jstahliv (Apr 13, 2016)

So after fixing the negative battery cable ( previous one was loose) the car was fine for a few days. Yesterday when I started going (18 degrees out) , i got P015b (o2 sensor delayed response-lean to rich) and p0302 (cylinder 2 misfire detected). Is my O2 sensor going out and should be replaced? Coil pack maybe next step. United nations did the coil pack fix it then?


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## dmagent99 (Aug 4, 2018)

so did the new coil end up working or did the issue come back ?


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## AutumnCruzeRS (Sep 10, 2012)

I had a similar issue like this too. Only on hard acceleration like on the on ramp to the freeway I would get this feel of a miss like I was loosing boost. I didn't get any codes so didn't have that to look into. I first thought it may of been a waste gate or bpv issue with the turbo. I was hesitate to get a new coil but it did have a crack in the gel pack so I kinda thru A new coil at it from Rockauto and it fixed all the issue there. I was over 100k miles with the original coil too.


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## lonewolf04 (May 6, 2016)

There is also a TSB to replace the coil pack connector end. 

#16-NA-015: Engine Stall or Stumble - Replace Coil Connector - (Jan 21, 2016)


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## jstahliv (Apr 13, 2016)

Where is this " Coil Connector". I have put in a new battery, new neg. batt cable, new coil pack, new intake manifold (cause of STUPID CHECK VALVE FAILURE/MISSING), new spark plugs (irridium/oem type not coppers) New valve cover (PCM valve went out)and fuel injector cleaner and different gas. Now I still have p0300! and the crazy U0100. Any updates and help for me?


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## cruze2014lt (Mar 11, 2021)

Did anyone figured the P0300 out? I am at 137k with my 2014 Cruze 1.4L and have already changed spark plugs at 95k with 3 new boots as they got stuck were deformed. I did install a new valve cover with bran new gasket a few months ago. It ran fine for the most part and couple days ago after high rpm it started misfiring. I cleaned the spark plugs with electronic cleaner and checked the boot coils for deformation or damage but nothing obvious. Really struggling with diagnosis here. Send help.


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## Cruzin2011 (Jul 5, 2020)

unitednations161 said:


> So i got my new coil pack, day one seems ok. It did stall on the cold start but these cars have issues starting when a temp change over night. Anyone else notice this?


Yes, I live in Florida and if it gets down to the 40’s or 30’s for a couple of nights, the car runs fine... but when I take it out when it’s75-80 degrees out, the car runs pretty crappy . I can smell gas coming out for the engine area and it only does this in the specific situation.

I have done this on all my cars I have owned... I will disconnect the negative battery terminal for a minute and then start the car up... it resets the ECM and forces it to relearn its environment.

not only does the car start better but it is faster. After resetting the ECM I will grab second gear and it rips the tire loose for a good 10 feet.

If I drive it for a few weeks, that goes away until I reset the ECM again.

I actually looking for a battery terminal for the ground that just has a switch I can flip in stead of disconnecting the actual battery terminal


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## cruze2014lt (Mar 11, 2021)

jstahliv said:


> Where is this " Coil Connector". I have put in a new battery, new neg. batt cable, new coil pack, new intake manifold (cause of STUPID CHECK VALVE FAILURE/MISSING), new spark plugs (irridium/oem type not coppers) New valve cover (PCM valve went out)and fuel injector cleaner and different gas. Now I still have p0300! and the crazy U0100. Any updates and help for me?


What did you ended up doing? I am a bit curious. I am kinda on similar route.


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