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Engine Cylinder misfire

Tiny
WARREN1814
  • MEMBER
  • 1999 LINCOLN TOWN CAR
  • 5.1L
  • V8
  • 2WD
  • AUTOMATIC
  • 82,000 MILES
Hello it's me again, Warren. This question is asked on the behave of my mother. She owns the car listed above. She went to change the spark plugs herself and she took the spark plug boot off and there was no spark plug in there at all. My question is, how is this car running with only 7 spark plugs and without any check engine light on what so ever? And it started to shake about 4 days ago. (23rd). And she has had the car since 2008. And nothing else has been changed on it and it was running good before.
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Monday, July 29th, 2019 AT 8:41 PM

34 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Welcome to 2CarPros.

It will run on 7 cylinders, but it obviously will have a misfire. I'm not sure how she checked, but here is a link that explains how to check. Also, it could be related to the coil pack itself of it is only one cylinder.

Please keep in mind, if you have no spark to one cylinder, it can allow raw fuel to enter the catalytic converter and damage it. Therefore, we need to find the problem before something more happens.

___________________

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Try checking using that technique and let me know what you find.

Here are a few links you may find helpful when checking:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

Let me know what you find.

Joe
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Monday, July 29th, 2019 AT 9:06 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,479 POSTS
Warren, "And it started to shake about 4 days ago." is the key to why the plug is missing. It did one of three things, The plug worked loose in the cylinder head and was blown out of the head, the center porcelain section of the plug came loose and was blown out or the most common reason is that the threads in the head failed and the plug blew out.

That would cause the shake and "missing plug". Why it didn't have a flashing check engine light is odd, have her look at the dash while the bulb check happens when the key is first turned on. Does the check engine light come on?
As to repairing it, If the threads in the cylinder head are okay I would just replace all the plugs. Being very careful not to over torque them as the threads in those heads are very easy to strip. If the threads are damaged then it is possible to use a kit to repair the threads. You can get the repair kits at many parts stores along with the tools as a loan a tool kit.
If the plug itself came apart either through rusting or other then removing the left over pieces and replacement should do the trick.
This isn't an uncommon thing on some Ford engines from 1998 to about 2002. The reason is that the threaded section of the head that retains the plug has only 4 full threads in the plug holes.
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Tuesday, July 30th, 2019 AT 12:00 AM
Tiny
WARREN1814
  • MEMBER
  • 142 POSTS
Hello and thank you for taking the time to answer. @Steve W. Yes the check engine light does come on. In fact that didn't come on until we got home. And when it did come on, It stayed on sold (none flashing) And yes I find that to be very odd that it didn't flash at all. @JACOBANDNICKOLAS She just said she removed everything and looked into the hole where the spark plug would be and didn't see anything. She will check on it again this afternoon and I will let you guys know what she finds.
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Tuesday, July 30th, 2019 AT 3:29 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Welcome back:

Follow the procedure I attached and see if there is spark. Also, have you retrieved the diagnostic trouble codes related to the check engine light being on?

Let me know.

Joe
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Tuesday, July 30th, 2019 AT 5:47 PM
Tiny
WARREN1814
  • MEMBER
  • 142 POSTS
Update: Well after taking her car in to get it service we discovered that the so called missing spark plug was still in there but the top half was broken off. There's a spark plug in there she just wasn't able to see it very well. And yes there was error codes. The first one was a P0113 and the 2nd one was a P0102. Now after getting her spark plugs replaced today she still says that when she is at a stop light and getting ready to go the car runs fine. But as soon as she steps on the gas the car still hesitates to go. Also, the repair guy told her while he was changing her spark plugs there is some oil leaking into one of her cylinders where the spark plug is at the back of the motor on the driver's side.
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Thursday, August 1st, 2019 AT 7:13 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Welcome back:

First, the oil leaking isn't actually into the cylinder. He may have confused you. What happens is the o-ring that seals the spark plug tower can leak allowing oil to enter the tower. That can eventually lead to a misfire.

The codes you have could be related to the hesitation. The P0102 is related to the mass air flow sensor (MAF). Some basic things you can check is to first make sure it is connected. Also, check to make sure there are no air leaks near it.

The other code, P0113 is related to the intake air temperature sensor (IAT). Interestingly both of these components are near each other and work together. So again, check to make sure it is securely plugged in and there are damaged wires going to it.

I attached two pics. The first shows the MAF. It is mounted on the air inlet tube (between the air filter box and intake manifold). The second pic shows the IAT. It is on the side of the air filter box.

Let me know what you find. I believe it is one of these two that are causing the hesitation.

Take care,
Joe
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Thursday, August 1st, 2019 AT 7:41 PM
Tiny
WARREN1814
  • MEMBER
  • 142 POSTS
Okay, I will keep you posted on this matter and my van as well.
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Thursday, August 1st, 2019 AT 10:36 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Welcome back:

Sounds like a plan. I will keep my eyes open for your reply.

Take care,
Joe
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Friday, August 2nd, 2019 AT 7:36 PM
Tiny
WARREN1814
  • MEMBER
  • 142 POSTS
Update on the Town car: Well as of now all of the spark plugs have been replaced as I said earlier and the check engine light was still on when we came home. And we both looked at each other and said something isn't right. With the spark plugs replaced that light should have went off but it didn't. So we drove it home and looked under the hood and discovered the repair guy didn't even reconnect the mas sensor and the intake air temp sensor back up at all. Plugs where just sitting completely disconnected. So after discovering they where unplugged and everything we decided to clean everything up before plugging things back up with some CRC mass air flow cleaner and then see what will happened. And clear the codes too. And so far the service engine soon light has not come on so far and it no longer stutters when she hits the gas. My mother is so happy but. Time will tell if this fixed the problem or was it just the spark plugs was bad etc. Oh yeah, the repair guy told her he fixed it some kind of way temperately so the oil wouldn't leak back into that spark plug tower. Now what he did I have no idea. We didn't stay and watch what he did. Etc
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Tuesday, August 6th, 2019 AT 11:15 PM
Tiny
WARREN1814
  • MEMBER
  • 142 POSTS
Thank you for all of you help with my mother's town car. As I keep saying. This is a great web site. Keep up the good work guys! :-) If anything comes up about the town car I will let you guys know about that too.
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Wednesday, August 7th, 2019 AT 9:47 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,479 POSTS
Not sure myself what he would have done as a temporary fix, cleaned it very well and applied some sealer would be my guess. Thank you for keeping us informed, we get a lot of people that just vanish after they get an answer. We will be here if you need us. Thank you for using 2CarPros. Tell a friend or 100 about us.
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Thursday, August 8th, 2019 AT 6:52 AM
Tiny
WARREN1814
  • MEMBER
  • 142 POSTS
That's what I was thinking too. Time will tell though. So far the car is running good etc. And you are welcome. I figured if someone takes the time to give you an answer at least a person could do is stick around. And who knows if you stick around longer then that you just may learn something new for a newer problem you might have too etc. And not to worry I plan on telling everyone I know about your site. I think it is a great site. And it is free too. You can't beat that at all.
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Friday, August 16th, 2019 AT 3:01 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Nice to hear from you again. Glad to hear it is still running good for you. Stay in touch if you need help with anything.

Take care,
Joe
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Friday, August 16th, 2019 AT 7:41 PM
Tiny
LUKEBARAZAN
  • MEMBER
  • 1 POST
  • 1999 LINCOLN TOWN CAR
  • 4.6L
  • V8
  • 2WD
  • AUTOMATIC
  • 1,500,000 MILES
Troubles are no spark at ignition coil number four, five, six, and eight.
I already check and simulate the following:
ignition coil.
Crankshaft sensor.
Cam sensor.
Spark plug.
Check it if there is open or any short circuit along the lines in between PCM and connectors of ignition coil, fuel injectors, but the line are okay.
Same trouble occur no spark at cylinder numbers four, five, six, and eight.
Compression test it, okay.
The only problems is no spark at coil number four, five, six, and eight.

Is this a common trouble for vehicle TC?
This is new for me.

Thanks
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Saturday, December 19th, 2020 AT 9:45 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,690 POSTS
Hello,

It sounds like the coil drivers inside the PCM are bad I would get a used one and swap it out. Below is the location.

Check out the diagrams (below).

Please let us know what you find.

Cheers, Ken
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Saturday, December 19th, 2020 AT 9:45 AM (Merged)
Tiny
LBARAZAN
  • MEMBER
  • 4 POSTS
Thank you so much for answering my question it has made me feel enlighten. However, I already did it to swapping from same model but it will not work due to immobilizer system block but I suspect the PCM.
May I ask something if possible, is the PCM repairable?
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Saturday, December 19th, 2020 AT 9:45 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,690 POSTS
It could be but only a re-builder can tell you that. When you switched the PCM the security light flashed?
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Saturday, December 19th, 2020 AT 9:45 AM (Merged)
Tiny
LBARAZAN
  • MEMBER
  • 4 POSTS
Thanks Mr Ken.

I believed so that what happened during swapping of PCM.
What I did is I take the following parts from the troubled unit and install to other good unit.
Immobilizer Ring. Immobilizer control module. Key ignition unit. And the result the security light keeps flashing that why the engine won't start.
May Question is. It is possible to switch the the immobilizer unit from other vehicle with the same model for just a reference to know if the pcm is really in trouble?
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Saturday, December 19th, 2020 AT 9:45 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,690 POSTS
Not really because the ring is just the antenna which delivers the chip frequency to the computer key. This is why the car must go to someone that can program the key in. Should cost about $130.00
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Saturday, December 19th, 2020 AT 9:45 AM (Merged)
Tiny
MILKCOOL
  • MEMBER
  • 1 POST
  • 1999 LINCOLN TOWN CAR
  • 175,000 MILES
How to check for spark? Having misfire number three.
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Saturday, December 19th, 2020 AT 9:45 AM (Merged)

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