There are other possibilities here (1) when you changed coil packs did you change the whole thing /coil+ boots/?, if you only did the coil and not the boots ,the boots can be either soft leaking the + voltage to the engine ground or they have a Crack in them ,check for this by rolling the boots in your fingers this will display the splits at the bottom and soft mushy feeling that will cause leaks also bend back n forth if it's real easy they are no good the boots should be rigid and only flex slightly, next inspect those cylinders for moisture in them ,oil leaking valve cover ,antifreeze leaking thermostat or crossover allowing coolant to travel down the cylinder head, water being that both misfires are in the same place on the engine across from each other check your inner fenders for breaks or missing splash shields allowing water to enter from hitting puddles in the rain/regular splash up from tires/or going through the car wash high pressure water forced spray will cause it to enter the cylinders if they are missing which are across from each other in the same spot on both sides which is pointing to blow back from the missing shields and road wind post back if still persistent
Does each cylinder have it's own coil ? (COP ) coil on plug ignition system . Is the PCM - controlling them ? Could have fried driver inside the PCM . How was the spark plug gap ? Worn - this can cause the coil short inside sending 20,000 volts to the PCM driver (transistor)
https://www.youtube.com/watch?v=y4r5OcHN5Lg
SOURCE: #5 cylinder misfire
I have a corolla and had #4 cylinder misfire also diagnosed at autozone. After changing the spark plugs, problem persisted, along with the same error code, so they recommended changing the spark plug wires, and that is what fixed it. I would have changed the rotor cap too, but was low on dough. Glad that was not the problem.
SOURCE: engine code p0307 cylinder #7 misfire
It could be carbon deposits on valve seats keeping valves from totally closing. You can try getting you a can of motorcraft PM3 top end engine cleaner and get engine up to operating temp then remove one of the small vacuum lines from the intake and draw the contents of the can slowly into the engine.After you have drawn in the contents shut engine off and let it soak for about 45 minutes then crank it back up and let it run until it clears. Now it will smoke like a forrest fire while you are doing this so don't be alarmed,just tell the neighbors you are spraying for mosqitos.This may cure the problem. If not you may be looking at a valve job.
This can be verified with a compression test if this is what is causing it.
SOURCE: MISFIRING ON CYLINDER 1 VW POLO 1.4 3CYLINDER
I have changed a few cylinder heads under warranty for this type of problem. The exhaust valve guides wear, this causes the exhaust valve to seat badly, giving low compression. if one cylinder compresion reading is more than about 50 psi below the others, then this warrants head removal. It is quite a job, due to the fact that the camshft id chain driven. If you are up for it then once the head is removed, poor liquid into the exhaust ports and see if it leaks out through any of the exhaust valves.
SOURCE: 1997 ford f150 cyliner 7 misfire
After replacing the coil, plug and wire. The injector is working properly so I would say that you have a burnt exhaust valve. Get a cylinder leak down test or compression test to confirm this at a reputable mechanic.
It can be issue with spark plugs or faulty spark plugs. Also
get the compression test done for cylinders. If any of cylinder shows low
compression then required, then that particular cylinder will cause misfire.
Also get obd codes scanned, the error code will let you know
which cylinder is misfiring or all cylinders are misfiring.
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For your trouble shooting I suggest you to refer the help
oinks below. It has step by step details for many engine misfire issues.
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Click the link below:-----
Ford Explorer Cylinder Misfire?
http://whoisbyme.blogspot.in/2012/06/ford-explorer-cylinder-misfire.html
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Engine Misfire codes on Chevrolet Malibu?
http://schematicsdiagram.blogspot.com/2011/12/engine-misfire-codes-on-chevrolet.html
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Cylinder 6 Misfire?
http://howtobyme.blogspot.com/2011/12/cylinder-6-misfire.html
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Misfire on cylinder 4?
http://schematicsdiagram.blogspot.com/2011/12/misfire-on-cylinder-4.html
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While stop engine idles like cylinder missing?
http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html
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Ford Explorer 5.0L: Engine Miss?
http://whoisbyme.blogspot.in/2012/06/ford-explorer-50l-engine-miss.html
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Oil on spark plugs and car misfires?
http://technoanswers.blogspot.in/2012/02/oil-on-spark-plugs-and-car-misfires.html
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Can cylinder misfire Damage the Catalytic converter?
http://schematicsdiagram.blogspot.in/2012/02/can-cylinder-misfire-damage-catalytic.html
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Car misfires and error code P0306 and P0303 is shown?
http://technoanswers.blogspot.com/2012/01/car-misfires-and-error-code-p0306-and.html
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Chevrolet K1500 No spark, random misfire
http://repairhelpcenter.blogspot.com/2012/11/chevrolet-k1500-no-sparkrandom-misfire.html
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2004 Ford F150: Engine Misfire and Lean Code?
http://whatisbyme.blogspot.in/2012/05/2004-ford-f150-engine-misfire-and-lean.html
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1995 Toyota LS: Misfire at idle or low RPM
http://whatisbyme.blogspot.in/2012/04/1995-toyota-ls-misfire-at-idle-or-low.html
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Toyota Corolla:
Random Misfire?
http://technoanswers.blogspot.in/2012/04/toyota-corolla-random-misfire.html
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2006 Ford Freestar: Misfire on Cylinder Number 2?
http://whatisbyme.blogspot.in/2012/06/2006-ford-freestar-misfire-on-cylinder.html
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This will help.
Thanks.
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