2004 Ford Expedition diagnostic codes

Tiny
BHUGG
  • MEMBER
  • 2004 FORD EXPEDITION
  • V8
  • 4WD
  • AUTOMATIC
  • 71,000 MILES
I reciently had a cylinder mis-firing that appeared to only be a loose connection. That problem triggered a check engine light. I have been monitoring the code checker to see if the misfire reappeares and have noticed that I have 2 monitoring tests that have not run if I read the information properly as they keep flashing on the monitor.

I also have a yellow light indicating the non running of these monitors. I have cycled the car through several trips and after saving the data off the computer, I reset the computer. It has not illumintated the check engine lamp and there are no diagnostic toruble codes stored in the computer.

The tests are the catalist monitor and the EVAP system monitor. I just had the smog checked last week and it passed in all catigories.

Am I too worried about these test not performing or should I be looking for something that I need to do?

Could the smog check people done something in the course of their testing that would have created this problem?
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Saturday, August 7th, 2010 AT 11:26 AM

5 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
If the car is running good, I would let it go unless the check engine light comes back on.
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Saturday, August 7th, 2010 AT 11:13 PM
Tiny
BHUGG
  • MEMBER
Well I guess that what I thought was loose connection turned out to be more than that.
The misfire on cylinder #8 is back.

I have checked for the sound of the fuel injector firing and that seems good and the coil over the plug has the proper resistance readings.
I have not pulled the plug as it is not in an easy location and I didn't have the time this weekend.
I guess that I will take it into the shop and have them look at it and see what happens.

BTW, the monitors did finally clear up.
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Monday, August 9th, 2010 AT 12:42 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Let me know what you find.
Joe
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Monday, August 9th, 2010 AT 1:16 AM
Tiny
BHUGG
  • MEMBER
I took it to the mechanic today and, of course, it worked fine for them. They went ahead and replaed the plug and coil. They stated that this is a common problem and this usually fixes it.

We will see if the problem comes back. There is no apparent damage or defect to either the plug or the coil assembly.

The coil appears to be good and the coil resistance was in line with the specs.

What should the resistance across the plug be? I can't get a reading on any scale up to 200k.

Could this be a problem?
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Monday, August 9th, 2010 AT 8:28 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
There shouldn't be any resistance in a plug. At least noting you can get a reading of. Let me know if the problem comes back or if you have other questions.

Joe
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Tuesday, August 10th, 2010 AT 11:15 PM

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