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Thread: Having an issue diagnosing a misfire P0306

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    Default Having an issue diagnosing a misfire P0306

    Hey, I am having a misfire issue that I'm having trouble diagnosing. I have a 2009 G8 GT. I received a check engine light with a flashing engine indicator while driving and noticed rough idle (and lurching) at low RPMs. I had the code read and it is indicating a misfire on cylinder 6 (P0306). I have replaced all the spark plugs and spark plug cables. I have swapped out coil pack 6 with coil pack 1. I have swapped fuel injector 6 with fuel injector 2. Checked compression on cylinder 6 and the gauge read just under 150 psi. I also verified that I'm getting spark. With those steps I'm still getting the misfire on cylinder 6 and rough idle/lurching at low rpms. It seems to run smoothly at higher RPMs. I also noticed that I had a little white smoke coming out of the passenger exhaust pipe along with a few drops of clear fluid. I'm not sure what to look at next. I'm hoping someone more experienced can point me in the right direction.

    Thanks,

    Michael

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    hi
    i have Chevrolet caprice 2009 v8 6.0 ltr
    im having same problem but with cylinder 7 , (p0307) , often it accrues in idle or low speed , i replaces all spark plugs , i cleaned fuel injectors and swapped its position , i checked the cables and swapped the coils , but problem still exist .
    i think the last thing we should do is replacing crank shaft position sensor .

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    Member chevybernie's Avatar
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    Hi.
    My Tahoe had last year this problem on one cylinder. There was a small cable directly one Millimeter behind the connector of the injector nozzle broken. This was hard to find, because insulation had only a little crack. On my Sonīs Trailblazer this year it was the position sensor. Engine started, maybe it runs for any kilometers without problems, but on the next traffic light, or stop, the motor runs always slower and goes out. We searched any days. Then at last we bought a new sensor and it runs great.

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    Quote Originally Posted by mdgarcia View Post
    Hey, I am having a misfire issue that I'm having trouble diagnosing. I have a 2009 G8 GT. I received a check engine light with a flashing engine indicator while driving and noticed rough idle (and lurching) at low RPMs. I had the code read and it is indicating a misfire on cylinder 6 (P0306). I have replaced all the spark plugs and spark plug cables. I have swapped out coil pack 6 with coil pack 1. I have swapped fuel injector 6 with fuel injector 2. Checked compression on cylinder 6 and the gauge read just under 150 psi. I also verified that I'm getting spark. With those steps I'm still getting the misfire on cylinder 6 and rough idle/lurching at low rpms. It seems to run smoothly at higher RPMs. I also noticed that I had a little white smoke coming out of the passenger exhaust pipe along with a few drops of clear fluid. I'm not sure what to look at next. I'm hoping someone more experienced can point me in the right direction.

    Thanks,

    Michael
    I'm in the same boat. What wound up being the fix?? Everything is exactly as how you explained it: cylinder 6 misfire, a little white smoke, CEL, I've switched and swapped everything listed, and it's still misfiring

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    Having an identical problem. Mine is also throwing P0700 and disabling ESC on occasion as well.

    Any resolution to this?

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    Was there any fix to the problem I'm having the same problem now

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    Did you ever end up fixing the problem I'm having the same problem now

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    funny i am now seeing this as i am having a similar issue, but no check eng lights or codes that i am aware of. feels like a rough idle to me but all very similar, any thought's i am happy to try. thanks

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    If it were the Crankshaft Position Sensor, I would think that it would be setting a code for that. I think I remember the tach becoming erratic on an LS7 that developed this problem. The white smoke makes me suspect a coolant leak into the cylinder. I hope that that is not the case, but that's what it sounds like to me. First thing I would look at would be for frothy looking oil on the dipstick.

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    Ha! I just realized that this is a four year old post!

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