Help with rough idle and acceleration - TIA
#81
Guest
Posts: n/a
Re: Help with rough idle and acceleration - TIA
I can't speak on the picture you posted, but what is used on the current 4.0L is
ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
If one coil doesn't work, 2 plugs don't get spark.
In message <4327952F.B28B9937@***.net>, "L.W." wrote:
> Even though it looks like one coil, there must be two inside as we
>know electricity follows the path of least resistance. And so like my
>Harley they are both triggered by single ignition hot discharge wire.
> God Bless America, Bill O|||||||O
>mailto:-------------------- http://www.----------.com/
>
>bllsht wrote:
>>
>> Oh, so the waste spark system on the 4.0L different than the waste spark system
>> on any other engine? Please explain.
ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
If one coil doesn't work, 2 plugs don't get spark.
In message <4327952F.B28B9937@***.net>, "L.W." wrote:
> Even though it looks like one coil, there must be two inside as we
>know electricity follows the path of least resistance. And so like my
>Harley they are both triggered by single ignition hot discharge wire.
> God Bless America, Bill O|||||||O
>mailto:-------------------- http://www.----------.com/
>
>bllsht wrote:
>>
>> Oh, so the waste spark system on the 4.0L different than the waste spark system
>> on any other engine? Please explain.
#82
Guest
Posts: n/a
Re: Help with rough idle and acceleration - TIA
I can't speak on the picture you posted, but what is used on the current 4.0L is
ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
If one coil doesn't work, 2 plugs don't get spark.
In message <4327952F.B28B9937@***.net>, "L.W." wrote:
> Even though it looks like one coil, there must be two inside as we
>know electricity follows the path of least resistance. And so like my
>Harley they are both triggered by single ignition hot discharge wire.
> God Bless America, Bill O|||||||O
>mailto:-------------------- http://www.----------.com/
>
>bllsht wrote:
>>
>> Oh, so the waste spark system on the 4.0L different than the waste spark system
>> on any other engine? Please explain.
ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
If one coil doesn't work, 2 plugs don't get spark.
In message <4327952F.B28B9937@***.net>, "L.W." wrote:
> Even though it looks like one coil, there must be two inside as we
>know electricity follows the path of least resistance. And so like my
>Harley they are both triggered by single ignition hot discharge wire.
> God Bless America, Bill O|||||||O
>mailto:-------------------- http://www.----------.com/
>
>bllsht wrote:
>>
>> Oh, so the waste spark system on the 4.0L different than the waste spark system
>> on any other engine? Please explain.
#83
Guest
Posts: n/a
Re: Help with rough idle and acceleration - TIA
I can't speak on the picture you posted, but what is used on the current 4.0L is
ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
If one coil doesn't work, 2 plugs don't get spark.
In message <4327952F.B28B9937@***.net>, "L.W." wrote:
> Even though it looks like one coil, there must be two inside as we
>know electricity follows the path of least resistance. And so like my
>Harley they are both triggered by single ignition hot discharge wire.
> God Bless America, Bill O|||||||O
>mailto:-------------------- http://www.----------.com/
>
>bllsht wrote:
>>
>> Oh, so the waste spark system on the 4.0L different than the waste spark system
>> on any other engine? Please explain.
ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
If one coil doesn't work, 2 plugs don't get spark.
In message <4327952F.B28B9937@***.net>, "L.W." wrote:
> Even though it looks like one coil, there must be two inside as we
>know electricity follows the path of least resistance. And so like my
>Harley they are both triggered by single ignition hot discharge wire.
> God Bless America, Bill O|||||||O
>mailto:-------------------- http://www.----------.com/
>
>bllsht wrote:
>>
>> Oh, so the waste spark system on the 4.0L different than the waste spark system
>> on any other engine? Please explain.
#84
Guest
Posts: n/a
Re: Help with rough idle and acceleration - TIA
I knew that. Just wanted to be clear for those others who like to argue. :-)
In message <TNednRFBXazWIbXenZ2dnUVZ_sudnZ2d@comcast.com>, "Matt Macchiarolo"
wrote:
>OK, that's what I meant...
>
>"bllsht" <nospam@invaliddot.net> wrote in message
>news:8mo9i1h18n35h5ts8rc62sg0qtj6hrm9ua@4ax.com.. .
>> Actually, it's 1 coil pack containing 3 coils. Each coil operating 2
>> cylinders.
>>
>> In message <uqidnXAodsszSLneRVn-pQ@comcast.com>, "Matt Macchiarolo"
>> wrote:
>>
>>>That's the 4.0L, not the V-8. 4.0L I-6 uses three coil packs, one per two
>>>plugs.
>>>
>>>"tim bur" <dbrider@cac.net> wrote in message
>>>news:43249F9E.6F32B587@cac.net...
>>>> not on that coil pac
>>>>
>>>> Billy Ray wrote:
>>>>
>>>>> Don't each of the coil packs handle 2 cylinders? Wouldn't both
>>>>> misfire?
>>>>>
>>>>> --
>>>>> .
>>>>> Billy_Ray@SPAM.fuse.net (remove SPAM)
>>>>> 2002 Jeep WJ 4 Liter Automatic
>>>>> Brilliant Black Crystal Pearl Coat
>>>>> Sharing is why we are all here....... or should be.
>>>>> .
>>>>> "tim bur" <dbrider@cac.net> wrote in message
>>>>> news:43236F02.32C2328F@cac.net...
>>>>> > fouled spark plug, failed injector, and a failed coil pac ,
>>>>> >
>>>>> > ken859@optonline.net wrote:
>>>>> >
>>>>> >> 2004 Jeep Grand Cherokee Limited
>>>>> >> Inline 6 Cylinder Engine
>>>>> >> Automatic Transmission
>>>>> >> Stock - No modifications
>>>>> >>
>>>>> >> Symptoms:
>>>>> >> After car warms up (3-5 Minutes) the engine idle drops to about
>>>>> >> 600RPM
>>>>> >> and the car starts shaking rapidly. When you accelerate the car
>>>>> >> shakes repeatedly between 600RPM and 1500RPM. At 50 miles an hour,
>>>>> >> pressing the accelerator slightly to maintain a steady velocity
>>>>> >> (which
>>>>> >> is about 1500RPM) the car will experience the shake while driving.
>>>>> >> Moderate acceleration the problem goes away. Lifting off of the gas
>>>>> >> and the problem goes away until the above rpm range is reached and
>>>>> >> then problem comes back
>>>>> >>
>>>>> >> Followup:
>>>>> >> Computer diagnostics indicates a miss fire on cylinder # 5
>>>>> >>
>>>>> >> Question:
>>>>> >> Could this be a clogged injector or are there other suggestions?
>>>>> >>
>>>>> >> TIA Ken
>>>>> >
>>>>
>>>
>
In message <TNednRFBXazWIbXenZ2dnUVZ_sudnZ2d@comcast.com>, "Matt Macchiarolo"
wrote:
>OK, that's what I meant...
>
>"bllsht" <nospam@invaliddot.net> wrote in message
>news:8mo9i1h18n35h5ts8rc62sg0qtj6hrm9ua@4ax.com.. .
>> Actually, it's 1 coil pack containing 3 coils. Each coil operating 2
>> cylinders.
>>
>> In message <uqidnXAodsszSLneRVn-pQ@comcast.com>, "Matt Macchiarolo"
>> wrote:
>>
>>>That's the 4.0L, not the V-8. 4.0L I-6 uses three coil packs, one per two
>>>plugs.
>>>
>>>"tim bur" <dbrider@cac.net> wrote in message
>>>news:43249F9E.6F32B587@cac.net...
>>>> not on that coil pac
>>>>
>>>> Billy Ray wrote:
>>>>
>>>>> Don't each of the coil packs handle 2 cylinders? Wouldn't both
>>>>> misfire?
>>>>>
>>>>> --
>>>>> .
>>>>> Billy_Ray@SPAM.fuse.net (remove SPAM)
>>>>> 2002 Jeep WJ 4 Liter Automatic
>>>>> Brilliant Black Crystal Pearl Coat
>>>>> Sharing is why we are all here....... or should be.
>>>>> .
>>>>> "tim bur" <dbrider@cac.net> wrote in message
>>>>> news:43236F02.32C2328F@cac.net...
>>>>> > fouled spark plug, failed injector, and a failed coil pac ,
>>>>> >
>>>>> > ken859@optonline.net wrote:
>>>>> >
>>>>> >> 2004 Jeep Grand Cherokee Limited
>>>>> >> Inline 6 Cylinder Engine
>>>>> >> Automatic Transmission
>>>>> >> Stock - No modifications
>>>>> >>
>>>>> >> Symptoms:
>>>>> >> After car warms up (3-5 Minutes) the engine idle drops to about
>>>>> >> 600RPM
>>>>> >> and the car starts shaking rapidly. When you accelerate the car
>>>>> >> shakes repeatedly between 600RPM and 1500RPM. At 50 miles an hour,
>>>>> >> pressing the accelerator slightly to maintain a steady velocity
>>>>> >> (which
>>>>> >> is about 1500RPM) the car will experience the shake while driving.
>>>>> >> Moderate acceleration the problem goes away. Lifting off of the gas
>>>>> >> and the problem goes away until the above rpm range is reached and
>>>>> >> then problem comes back
>>>>> >>
>>>>> >> Followup:
>>>>> >> Computer diagnostics indicates a miss fire on cylinder # 5
>>>>> >>
>>>>> >> Question:
>>>>> >> Could this be a clogged injector or are there other suggestions?
>>>>> >>
>>>>> >> TIA Ken
>>>>> >
>>>>
>>>
>
#85
Guest
Posts: n/a
Re: Help with rough idle and acceleration - TIA
I knew that. Just wanted to be clear for those others who like to argue. :-)
In message <TNednRFBXazWIbXenZ2dnUVZ_sudnZ2d@comcast.com>, "Matt Macchiarolo"
wrote:
>OK, that's what I meant...
>
>"bllsht" <nospam@invaliddot.net> wrote in message
>news:8mo9i1h18n35h5ts8rc62sg0qtj6hrm9ua@4ax.com.. .
>> Actually, it's 1 coil pack containing 3 coils. Each coil operating 2
>> cylinders.
>>
>> In message <uqidnXAodsszSLneRVn-pQ@comcast.com>, "Matt Macchiarolo"
>> wrote:
>>
>>>That's the 4.0L, not the V-8. 4.0L I-6 uses three coil packs, one per two
>>>plugs.
>>>
>>>"tim bur" <dbrider@cac.net> wrote in message
>>>news:43249F9E.6F32B587@cac.net...
>>>> not on that coil pac
>>>>
>>>> Billy Ray wrote:
>>>>
>>>>> Don't each of the coil packs handle 2 cylinders? Wouldn't both
>>>>> misfire?
>>>>>
>>>>> --
>>>>> .
>>>>> Billy_Ray@SPAM.fuse.net (remove SPAM)
>>>>> 2002 Jeep WJ 4 Liter Automatic
>>>>> Brilliant Black Crystal Pearl Coat
>>>>> Sharing is why we are all here....... or should be.
>>>>> .
>>>>> "tim bur" <dbrider@cac.net> wrote in message
>>>>> news:43236F02.32C2328F@cac.net...
>>>>> > fouled spark plug, failed injector, and a failed coil pac ,
>>>>> >
>>>>> > ken859@optonline.net wrote:
>>>>> >
>>>>> >> 2004 Jeep Grand Cherokee Limited
>>>>> >> Inline 6 Cylinder Engine
>>>>> >> Automatic Transmission
>>>>> >> Stock - No modifications
>>>>> >>
>>>>> >> Symptoms:
>>>>> >> After car warms up (3-5 Minutes) the engine idle drops to about
>>>>> >> 600RPM
>>>>> >> and the car starts shaking rapidly. When you accelerate the car
>>>>> >> shakes repeatedly between 600RPM and 1500RPM. At 50 miles an hour,
>>>>> >> pressing the accelerator slightly to maintain a steady velocity
>>>>> >> (which
>>>>> >> is about 1500RPM) the car will experience the shake while driving.
>>>>> >> Moderate acceleration the problem goes away. Lifting off of the gas
>>>>> >> and the problem goes away until the above rpm range is reached and
>>>>> >> then problem comes back
>>>>> >>
>>>>> >> Followup:
>>>>> >> Computer diagnostics indicates a miss fire on cylinder # 5
>>>>> >>
>>>>> >> Question:
>>>>> >> Could this be a clogged injector or are there other suggestions?
>>>>> >>
>>>>> >> TIA Ken
>>>>> >
>>>>
>>>
>
In message <TNednRFBXazWIbXenZ2dnUVZ_sudnZ2d@comcast.com>, "Matt Macchiarolo"
wrote:
>OK, that's what I meant...
>
>"bllsht" <nospam@invaliddot.net> wrote in message
>news:8mo9i1h18n35h5ts8rc62sg0qtj6hrm9ua@4ax.com.. .
>> Actually, it's 1 coil pack containing 3 coils. Each coil operating 2
>> cylinders.
>>
>> In message <uqidnXAodsszSLneRVn-pQ@comcast.com>, "Matt Macchiarolo"
>> wrote:
>>
>>>That's the 4.0L, not the V-8. 4.0L I-6 uses three coil packs, one per two
>>>plugs.
>>>
>>>"tim bur" <dbrider@cac.net> wrote in message
>>>news:43249F9E.6F32B587@cac.net...
>>>> not on that coil pac
>>>>
>>>> Billy Ray wrote:
>>>>
>>>>> Don't each of the coil packs handle 2 cylinders? Wouldn't both
>>>>> misfire?
>>>>>
>>>>> --
>>>>> .
>>>>> Billy_Ray@SPAM.fuse.net (remove SPAM)
>>>>> 2002 Jeep WJ 4 Liter Automatic
>>>>> Brilliant Black Crystal Pearl Coat
>>>>> Sharing is why we are all here....... or should be.
>>>>> .
>>>>> "tim bur" <dbrider@cac.net> wrote in message
>>>>> news:43236F02.32C2328F@cac.net...
>>>>> > fouled spark plug, failed injector, and a failed coil pac ,
>>>>> >
>>>>> > ken859@optonline.net wrote:
>>>>> >
>>>>> >> 2004 Jeep Grand Cherokee Limited
>>>>> >> Inline 6 Cylinder Engine
>>>>> >> Automatic Transmission
>>>>> >> Stock - No modifications
>>>>> >>
>>>>> >> Symptoms:
>>>>> >> After car warms up (3-5 Minutes) the engine idle drops to about
>>>>> >> 600RPM
>>>>> >> and the car starts shaking rapidly. When you accelerate the car
>>>>> >> shakes repeatedly between 600RPM and 1500RPM. At 50 miles an hour,
>>>>> >> pressing the accelerator slightly to maintain a steady velocity
>>>>> >> (which
>>>>> >> is about 1500RPM) the car will experience the shake while driving.
>>>>> >> Moderate acceleration the problem goes away. Lifting off of the gas
>>>>> >> and the problem goes away until the above rpm range is reached and
>>>>> >> then problem comes back
>>>>> >>
>>>>> >> Followup:
>>>>> >> Computer diagnostics indicates a miss fire on cylinder # 5
>>>>> >>
>>>>> >> Question:
>>>>> >> Could this be a clogged injector or are there other suggestions?
>>>>> >>
>>>>> >> TIA Ken
>>>>> >
>>>>
>>>
>
#86
Guest
Posts: n/a
Re: Help with rough idle and acceleration - TIA
I knew that. Just wanted to be clear for those others who like to argue. :-)
In message <TNednRFBXazWIbXenZ2dnUVZ_sudnZ2d@comcast.com>, "Matt Macchiarolo"
wrote:
>OK, that's what I meant...
>
>"bllsht" <nospam@invaliddot.net> wrote in message
>news:8mo9i1h18n35h5ts8rc62sg0qtj6hrm9ua@4ax.com.. .
>> Actually, it's 1 coil pack containing 3 coils. Each coil operating 2
>> cylinders.
>>
>> In message <uqidnXAodsszSLneRVn-pQ@comcast.com>, "Matt Macchiarolo"
>> wrote:
>>
>>>That's the 4.0L, not the V-8. 4.0L I-6 uses three coil packs, one per two
>>>plugs.
>>>
>>>"tim bur" <dbrider@cac.net> wrote in message
>>>news:43249F9E.6F32B587@cac.net...
>>>> not on that coil pac
>>>>
>>>> Billy Ray wrote:
>>>>
>>>>> Don't each of the coil packs handle 2 cylinders? Wouldn't both
>>>>> misfire?
>>>>>
>>>>> --
>>>>> .
>>>>> Billy_Ray@SPAM.fuse.net (remove SPAM)
>>>>> 2002 Jeep WJ 4 Liter Automatic
>>>>> Brilliant Black Crystal Pearl Coat
>>>>> Sharing is why we are all here....... or should be.
>>>>> .
>>>>> "tim bur" <dbrider@cac.net> wrote in message
>>>>> news:43236F02.32C2328F@cac.net...
>>>>> > fouled spark plug, failed injector, and a failed coil pac ,
>>>>> >
>>>>> > ken859@optonline.net wrote:
>>>>> >
>>>>> >> 2004 Jeep Grand Cherokee Limited
>>>>> >> Inline 6 Cylinder Engine
>>>>> >> Automatic Transmission
>>>>> >> Stock - No modifications
>>>>> >>
>>>>> >> Symptoms:
>>>>> >> After car warms up (3-5 Minutes) the engine idle drops to about
>>>>> >> 600RPM
>>>>> >> and the car starts shaking rapidly. When you accelerate the car
>>>>> >> shakes repeatedly between 600RPM and 1500RPM. At 50 miles an hour,
>>>>> >> pressing the accelerator slightly to maintain a steady velocity
>>>>> >> (which
>>>>> >> is about 1500RPM) the car will experience the shake while driving.
>>>>> >> Moderate acceleration the problem goes away. Lifting off of the gas
>>>>> >> and the problem goes away until the above rpm range is reached and
>>>>> >> then problem comes back
>>>>> >>
>>>>> >> Followup:
>>>>> >> Computer diagnostics indicates a miss fire on cylinder # 5
>>>>> >>
>>>>> >> Question:
>>>>> >> Could this be a clogged injector or are there other suggestions?
>>>>> >>
>>>>> >> TIA Ken
>>>>> >
>>>>
>>>
>
In message <TNednRFBXazWIbXenZ2dnUVZ_sudnZ2d@comcast.com>, "Matt Macchiarolo"
wrote:
>OK, that's what I meant...
>
>"bllsht" <nospam@invaliddot.net> wrote in message
>news:8mo9i1h18n35h5ts8rc62sg0qtj6hrm9ua@4ax.com.. .
>> Actually, it's 1 coil pack containing 3 coils. Each coil operating 2
>> cylinders.
>>
>> In message <uqidnXAodsszSLneRVn-pQ@comcast.com>, "Matt Macchiarolo"
>> wrote:
>>
>>>That's the 4.0L, not the V-8. 4.0L I-6 uses three coil packs, one per two
>>>plugs.
>>>
>>>"tim bur" <dbrider@cac.net> wrote in message
>>>news:43249F9E.6F32B587@cac.net...
>>>> not on that coil pac
>>>>
>>>> Billy Ray wrote:
>>>>
>>>>> Don't each of the coil packs handle 2 cylinders? Wouldn't both
>>>>> misfire?
>>>>>
>>>>> --
>>>>> .
>>>>> Billy_Ray@SPAM.fuse.net (remove SPAM)
>>>>> 2002 Jeep WJ 4 Liter Automatic
>>>>> Brilliant Black Crystal Pearl Coat
>>>>> Sharing is why we are all here....... or should be.
>>>>> .
>>>>> "tim bur" <dbrider@cac.net> wrote in message
>>>>> news:43236F02.32C2328F@cac.net...
>>>>> > fouled spark plug, failed injector, and a failed coil pac ,
>>>>> >
>>>>> > ken859@optonline.net wrote:
>>>>> >
>>>>> >> 2004 Jeep Grand Cherokee Limited
>>>>> >> Inline 6 Cylinder Engine
>>>>> >> Automatic Transmission
>>>>> >> Stock - No modifications
>>>>> >>
>>>>> >> Symptoms:
>>>>> >> After car warms up (3-5 Minutes) the engine idle drops to about
>>>>> >> 600RPM
>>>>> >> and the car starts shaking rapidly. When you accelerate the car
>>>>> >> shakes repeatedly between 600RPM and 1500RPM. At 50 miles an hour,
>>>>> >> pressing the accelerator slightly to maintain a steady velocity
>>>>> >> (which
>>>>> >> is about 1500RPM) the car will experience the shake while driving.
>>>>> >> Moderate acceleration the problem goes away. Lifting off of the gas
>>>>> >> and the problem goes away until the above rpm range is reached and
>>>>> >> then problem comes back
>>>>> >>
>>>>> >> Followup:
>>>>> >> Computer diagnostics indicates a miss fire on cylinder # 5
>>>>> >>
>>>>> >> Question:
>>>>> >> Could this be a clogged injector or are there other suggestions?
>>>>> >>
>>>>> >> TIA Ken
>>>>> >
>>>>
>>>
>
#87
Guest
Posts: n/a
Re: Help with rough idle and acceleration - TIA
An experiment would be to hook two spark plugs to a regular coil,
and you find only one will fire.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
bllsht wrote:
>
> I can't speak on the picture you posted, but what is used on the current 4.0L is
> ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
>
> If one coil doesn't work, 2 plugs don't get spark.
and you find only one will fire.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
bllsht wrote:
>
> I can't speak on the picture you posted, but what is used on the current 4.0L is
> ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
>
> If one coil doesn't work, 2 plugs don't get spark.
#88
Guest
Posts: n/a
Re: Help with rough idle and acceleration - TIA
An experiment would be to hook two spark plugs to a regular coil,
and you find only one will fire.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
bllsht wrote:
>
> I can't speak on the picture you posted, but what is used on the current 4.0L is
> ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
>
> If one coil doesn't work, 2 plugs don't get spark.
and you find only one will fire.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
bllsht wrote:
>
> I can't speak on the picture you posted, but what is used on the current 4.0L is
> ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
>
> If one coil doesn't work, 2 plugs don't get spark.
#89
Guest
Posts: n/a
Re: Help with rough idle and acceleration - TIA
An experiment would be to hook two spark plugs to a regular coil,
and you find only one will fire.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
bllsht wrote:
>
> I can't speak on the picture you posted, but what is used on the current 4.0L is
> ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
>
> If one coil doesn't work, 2 plugs don't get spark.
and you find only one will fire.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
bllsht wrote:
>
> I can't speak on the picture you posted, but what is used on the current 4.0L is
> ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
>
> If one coil doesn't work, 2 plugs don't get spark.
#90
Guest
Posts: n/a
Re: Help with rough idle and acceleration - TIA
We are not talking about a "regular" coil.
In message <4328FEDE.34158107@***.net>, "L.W." wrote:
> An experiment would be to hook two spark plugs to a regular coil,
>and you find only one will fire.
> God Bless America, Bill O|||||||O
>mailto:-------------------- http://www.----------.com/
>
>bllsht wrote:
>>
>> I can't speak on the picture you posted, but what is used on the current 4.0L is
>> ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
>>
>> If one coil doesn't work, 2 plugs don't get spark.
In message <4328FEDE.34158107@***.net>, "L.W." wrote:
> An experiment would be to hook two spark plugs to a regular coil,
>and you find only one will fire.
> God Bless America, Bill O|||||||O
>mailto:-------------------- http://www.----------.com/
>
>bllsht wrote:
>>
>> I can't speak on the picture you posted, but what is used on the current 4.0L is
>> ONE coil firing TWO plugs simultaneously in OPPOSITE polarity.
>>
>> If one coil doesn't work, 2 plugs don't get spark.