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P0307 Cylinder misfire code

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Old 02-04-2008, 11:09 PM   #1
goldendd
 
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Default P0307 Cylinder misfire code

P0307 Cylinder Misfire...Now that I know what it is, what is it? Misfire? Is it an injector, spark problem, how do you diagnose further? Just got a 2000 GT Convertible 4.6L 5 Speed today and the check engine light came on.
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Old 02-04-2008, 11:12 PM   #2
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Default RE: P0307 Cylinder misfire code

welcome to the forums and congrats on the car, sorry about the CEL. it could be a matter of things, run some injector cleaner through the system, replace the fuel filter if it hasnt been replaced recently, and check the spark plugs.

Edit: are you asking what may cause a missfire or what is a missfire?
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Old 02-04-2008, 11:33 PM   #3
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Default RE: P0307 Cylinder misfire code

Thank you. Yes I know what a misfire is but I want to know what is causing it. My code reader just says misfire in #7 cylinder. I thought about putting some injector cleaner but the misfire feels electrical.
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Old 02-05-2008, 12:40 AM   #4
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Default RE: P0307 Cylinder misfire code

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ORIGINAL: goldendd

Thank you. Yes I know what a misfire is but I want to know what is causing it. My code reader just says misfire in #7 cylinder. I thought about putting some injector cleaner but the misfire feels electrical.
could be a bad spark plug then. im not sure how it would feel "electrical" but im trying to keep an open mind and understand what you are saying.

is it constant though can you feel the missfire?

how does the car respond to WOT runs or throttle blips?

start off with some injector cleaner and a fuel filter, those are two things that should be done anyhow.
if the problem doesnt change i would check the plugs,coils, and boots.
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Old 02-05-2008, 10:24 AM   #5
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Default RE: P0307 Cylinder misfire code

if the misfire gets worsewhen you put your foot down at low revs then it's more than likely spark-related. replace the #7 plug then see if it still misses, if it does, your COP is probably done..... quite common on these cars
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Old 02-05-2008, 02:07 PM   #6
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Default RE: P0307 Cylinder misfire code

Had the same problem. I went ahead and swapped all the plugs and COP's. Cleared it up and is an easy do it yourself job, but as always a lil costly.
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Old 02-05-2008, 11:59 PM   #7
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Default RE: P0307 Cylinder misfire code

Thank you guys for all your help and suggestions. I pulled all the injector wires off one by one until there was no change in the idle. I replaced that spark plug and it corrected the problem. The plug I pulled out was in very bad shape which makes me think the previous owner had somthing against tune-ups. The car runs much better now and I am planning a complete tune-up in the very near future.
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Old 02-06-2008, 12:34 AM   #8
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Default RE: P0307 Cylinder misfire code

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ORIGINAL: goldendd

Thank you guys for all your help and suggestions. I pulled all the injector wires off one by one until there was no change in the idle. I replaced that spark plug and it corrected the problem. The plug I pulled out was in very bad shape which makes me think the previous owner had somthing against tune-ups. The car runs much better now and I am planning a complete tune-up in the very near future.
somethin you should do with any used car you buy, even if from a dealership.
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Old 12-14-2009, 07:39 PM   #9
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hey guys im going to hijack this thread jaja...

i just had the same problem today!! took it to autozone to get the code and i was po3o6...

the weird thing is that i just did a tune up to the car about 2 months ago...

my question is... can it still be a bad plug or a bad cop/??

thanks for the help guys!

oh yeah it also threw the o2 sensor code but that has been on there since i put my x-pipe on..

Last edited by naza; 12-14-2009 at 07:45 PM.
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Old 12-14-2009, 08:09 PM   #10
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OP - Make sure you torque down the plugs correctly. Do yourself a favor and do a search on spark plug blowout on here...
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Old 12-14-2009, 08:15 PM   #11
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mine was miss firing on 3, new coil pack fixed the issue.
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Old 12-14-2009, 09:31 PM   #12
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Quote:
Originally Posted by ct_white_stang View Post
OP - Make sure you torque down the plugs correctly. Do yourself a favor and do a search on spark plug blowout on here...
That will be the first thing i check tomorrow! Im pretty sure i got it really tight, but you never know...thanks

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mine was miss firing on 3, new coil pack fixed the issue.
Yeah, if thats the problem i might as well do all 8..
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Old 12-15-2009, 12:08 AM   #13
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Quote:
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That will be the first thing i check tomorrow! Im pretty sure i got it really tight, but you never know...thanks



Yeah, if thats the problem i might as well do all 8..
Don't just make the spark plugs really tight. You need to actually torque them to 14-16 ft/lbs. The heads only have 4 threads on them and improperly torqued (too little or too much) will blow them out.

Don't waste money replacing all the COP's. Take the #6 COP and swap it to another cylinder. If the misfire follows it, you know it's a bad COP. Just replace the bad one. No point in replacing 7 good COP's.
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Old 12-16-2009, 09:22 PM   #14
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Quote:
Originally Posted by Xemeth View Post
Don't just make the spark plugs really tight. You need to actually torque them to 14-16 ft/lbs. The heads only have 4 threads on them and improperly torqued (too little or too much) will blow them out.

Don't waste money replacing all the COP's. Take the #6 COP and swap it to another cylinder. If the misfire follows it, you know it's a bad COP. Just replace the bad one. No point in replacing 7 good COP's.
got home late from work so i couldnt check it...... didt have a torque wrench so i have no clue how tight i did them haha...

well the car has 108k on her so i wasnt sure if it was time for a COP change but if its not worth it ill just replace the one that is bad...
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Old 12-16-2009, 09:22 PM
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2000, 2002, 46, 5th, code, codes, cylinder, engine, ford, misfire, misfiring, mustang, p0307, repair, wat

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