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2002 Lincoln town car, no. 5 spark plug is misfiring


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Juche
Novice

Nov 22, 2012, 12:06 PM

Post #1 of 6 (5548 views)
2002 Lincoln town car, no. 5 spark plug is misfiring Sign In

In my 2002 town car, 112k, standard V8 engine, I had the timing chain worked on a couple of months ago. Ever since then I have had problems with the car shaking, accelerating, vibrating, etc. I couldn't figure out what the problem was, I thought it was either a fuel system or an electrical problem.

About 2 weeks ago the check engine light came on, I took it to a shop and it was the no. 5 spark plug was misfiring. So the guy at the shop erased the code. I had the 100k maintenance done on my car including replacing all 8 spark plugs. That didn't help, and the light came back on. I had it read at autozone and same thing, no. 5 spark plug.

The ignition coil connector clip that connects to the ignition coil had a problem, a latch that is supposed to hold it on was broken. So I bought a new one of those and had it spliced to the wires, then hooked to the ignition coil. Doing that improved but didn't fix the situation.

It used to be the check engine light was on or blinking constantly. Since I had that done a couple days ago the light has only blinked once (it blinked 5 times). The car sometimes idles and accelerates smoothly, sometimes it shakes. When the light came on I was driving at 55 and the car started shaking more than normal.

So what do I do now? I have considered buying a new ignition coil. I have also thought about replacing the vacuum tubes for the fuel injector. What else is there to look at? I hope the fuel injector itself isn't going bad. My understanding is my model doesn't have a distributor cap and replacing the ignition coil would be my next best move.

Why would this problem not be consistent? It used to be consistently bad until I had the ignition coil connector replaced. Now it is intermittent.

I have already tried fuel system cleaner in the tank, and I've tried water remover in case there was some water in my gas. Neither helped (I think the water remover may have made it worse). When I had my 100k maintenance done the mechanic put sea foam in the vacuum lines, it didn't make a difference.


(This post was edited by Juche on Nov 22, 2012, 12:12 PM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Nov 22, 2012, 12:49 PM

Post #2 of 6 (5509 views)
Re: 2002 Lincoln town car, no. 5 spark plug is misfiring Sign In

You know, doing/diagnosing your own work isn't always the cheaper way to go, especially when you don't know what you're doing. You've turned what would have been a very basic diagnosis by a qualified tech that most likely would have been free in many shops into something expensive and complicated. This engine is notorious for bad coils which would have been the first thing any knowledgeable tech would have gone to. I don't know what "vacuum tubes for the fuel injector" are supposed but there is no such thing. Replace the coil and pray you haven't ruined your Catalytic Converter by driving it that way.
For future reference, flashing lights on the dashboard generally mean "shut the car off immediately".



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Juche
Novice

Nov 22, 2012, 1:38 PM

Post #3 of 6 (5495 views)
Re: 2002 Lincoln town car, no. 5 spark plug is misfiring Sign In

I appreciate the reply. I did have the light read by a mechanic and he told me it was a spark plug misfiring, he erased the code and told me there was no harm in driving it. I did not know a blinking CEL was different from a regular CEL. I hope I haven't damaged the car. I will get the ignition coil replaced. The car has been at a mechanics for the last couple days as they try to figure out what is wrong. Ever since the ignition coil connector was replaced this problem is sporadic instead of constant.


(This post was edited by Juche on Nov 22, 2012, 1:39 PM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Nov 22, 2012, 2:52 PM

Post #4 of 6 (5471 views)
Re: 2002 Lincoln town car, no. 5 spark plug is misfiring Sign In

If this guy couldn't recognize a bad COP on a Ford and then tells you it's OK to drive, I wouldn't call him a mechanic. This is basic stuff. The flashing check engine light means that the misfire is severe enough to damage the Converter and shouldn't be driven.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Juche
Novice

Nov 30, 2012, 4:38 PM

Post #5 of 6 (5372 views)
Re: 2002 Lincoln town car, no. 5 spark plug is misfiring Sign In


In Reply To
You know, doing/diagnosing your own work isn't always the cheaper way to go, especially when you don't know what you're doing. You've turned what would have been a very basic diagnosis by a qualified tech that most likely would have been free in many shops into something expensive and complicated. This engine is notorious for bad coils which would have been the first thing any knowledgeable tech would have gone to. I don't know what "vacuum tubes for the fuel injector" are supposed but there is no such thing. Replace the coil and pray you haven't ruined your Catalytic Converter by driving it that way.
For future reference, flashing lights on the dashboard generally mean "shut the car off immediately".


Close but no. It was the ignition coil and the fuel injector that were going bad.

Replacing the ignition coil connector made the problem about 70% better. The CEL light came on sporadically and the car shook and hesitated, but not consisently.

A mechanic changed out the ignition coil by switching it with no. 7 and found it wasn't sparking as good as it should, so he installed a new ignition coil on no. 5. But that alone didn't fix the problem.

So he also replaced the fuel injector. That seems to have fixed it. I have driven it 250 miles since getting it back from the mechanic and I've had no shaking, hesitating, loss of acceleration, CELs etc. Of course that could come back who knows.

The real question is why would all these physical parts fail for the same cylinder. The coil connector wasn't connecting properly, the ignition coil wasn't sparking as well as it should and the fuel injector seems to have been damaged and it all occurred in the no. 5.

The catalytic converter is fine according to the mechanic.


(This post was edited by Juche on Nov 30, 2012, 4:39 PM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Nov 30, 2012, 4:48 PM

Post #6 of 6 (5365 views)
Re: 2002 Lincoln town car, no. 5 spark plug is misfiring Sign In

I don't believe it ever had a bad injector. I advised it was a bad coil from the beginning and I suspect he just forgot to plug the injector back in when he was playing with the coils. I fix these things all the time and I have changed hundreds of coils and not even one injector. If the guy had any experience in these engines, he would have immediately recognized the bad coil.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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