misfiring
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misfiring
I has a 1999 ford explorer sport 4X4 with about 110000 mile on it. I am getting an check engine lights. So I went to Autozone and check the codes. the codes was P0304 which is #4 cylinder was misfiring. They told me to change the spark plug and that would correct the problem. I change the spark plug and the wire and it is still giving me the check engine light. And when i drive it, it runs bad but idle smooth. when I getted to a stop light i can here the engine missing. Just wonder what to do next. My engine is a 4.0 EFI V6.
Postmaster
Joined: Jan 2003
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From: Durham, NC
Originally Posted by danr1
Replace the coil/pack that includes that cylinder.
there could be a carbon track on the coil pack plug wire post for #4.
Lead Driver
Joined: Aug 2006
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From: Sand Lake, MI
Originally Posted by Bob Ayers
With the EDIS coil packs, the secondary winding drives 2 plugs. If there is a coil pack failure, it normally will cause misfire on 2 plugs. With one exception,
there could be a carbon track on the coil pack plug wire post for #4.
there could be a carbon track on the coil pack plug wire post for #4.
However, always best to fully test any part you can before replacement.
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Chnaged the coil pack and the problem of misfiring got worst. The check engine light went off and has stay off for a couple of days. More detail about the problem. when I first start the truck up, it runs fine. as soon as i changed gear, it start misfiring . It will sound that way until it warm up. At the bottom of the truck I am heard a blowing or sucking noise. When going around curve the truck is having an hard time pulling it self out of the curve. The splatting continue when I put any load on the engine.
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From: Sand Lake, MI
It's starting to sound like a compression test may be in order, if you find that #4 cylinder is very low, squirt some motor oil in the hole and see if it raises the reading in that cylinder. it it does it's worn bad, if it has no effect you have a serious machanical falure. rings, piston, gasket, bent or burnt valve.
To do a proper test remove all the spark plugs, a screw in tester works better than the type held against the plug hole) whichever one is used be sure to turn the motor over so the cylinder you are testing hits on the compression stroke 3 times and builds full pressure. Wrirte down the result for each cylinder.
Compare numbers and look for an even reading accross all cylinders, more important than a "high" reading a book calls for. (you are looking for one or even two that have very low, or no compression)
If you find a low one try the motor oil test. (Couple tablespoons full or so)
Please let us know how you make out if you decide to do the test, Dan
To do a proper test remove all the spark plugs, a screw in tester works better than the type held against the plug hole) whichever one is used be sure to turn the motor over so the cylinder you are testing hits on the compression stroke 3 times and builds full pressure. Wrirte down the result for each cylinder.
Compare numbers and look for an even reading accross all cylinders, more important than a "high" reading a book calls for. (you are looking for one or even two that have very low, or no compression)
If you find a low one try the motor oil test. (Couple tablespoons full or so)
Please let us know how you make out if you decide to do the test, Dan
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