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Old 04-13-2010, 03:36 PM   #1
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Default How important is dielectric grease?

Okay I understand it is important in the long run. BUT...

I just replaced all 8 ignition coils and the overdrive shudder seems to be worse and the check engine light started flashing today and i had to turn O/D off for the truck to stop shaking on the highway. I will admit I did not use dielectric grease on any of the new COPs. I understand dielectric grease does not help conduct electricity, but just the opposite in order to protect the contacts from corrosion. Could my lack of the grease be causing a misfire in overdrive?

FYI even though the check engine light is off Advance Auto still found a code for misfire in cylinder 7 (P0307).


any help is appreciated!
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Old 04-13-2010, 03:39 PM   #2
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I can't see the dielectric grease or lack there of causing a misfire. Just there for corrosion resistance. Sounds like you may still have a bad coil or plug.

Kev
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Old 04-13-2010, 07:49 PM   #3
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The dielectric wont be an issue now. Long run maybe but not causing your issue. So it runs fine with overdrive off but not in overdrive? Did the coil wires all push on completely? You sure its not tranny related?
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Old 04-13-2010, 08:02 PM   #4
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I would put money on the coil not being on all the way or not sitting on the plug properly.
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Old 04-13-2010, 08:56 PM   #5
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Guys these new coils on the 04-and newer trucks just don't quite like the previous 04 heritage and older models you need to change the spark plugs there has been numerous updates to the early version of those spark plugs for misfire issues, Ya those plugs are not fun to get out.... but they will comeout this will fix your concern. good luck..

The other issue is fuel injectors they will stick closed and open filling the cylinder full of fuel
there is a program through ford that will cover bad injectors up to I BELIEVE 150K at no charge to you..
good luck

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Old 04-14-2010, 09:56 AM   #6
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Would the issue be with a plug if the misfire is only happening in overdrive?

I would think if it were a plug the truck would misfire at all speeds and all RPM ranges. From what I've read the ignition coils fail when under stress (ie: overdrive trying to climb slight incline).

I guess my question is, would the extra load of climbing a slight incline in overdrive be enough to cause a misfire with a plug?

Also it never, ever happens when the engine is cold in the morning, only after it heats up.

Ford dealer diagnosed it as 2 bad COPs and 4 bad plugs, Advance Auto said cylinder 7 misfire... so I'm convinced this is not a tranny issue.

What about a computer flash or reset or whatever? I don't know too much about that, but could this change anything?
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Old 04-14-2010, 08:36 PM   #7
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Quote:
Originally Posted by truckbed View Post
Would the issue be with a plug if the misfire is only happening in overdrive?

I would think if it were a plug the truck would misfire at all speeds and all RPM ranges. From what I've read the ignition coils fail when under stress (ie: overdrive trying to climb slight incline).

I guess my question is, would the extra load of climbing a slight incline in overdrive be enough to cause a misfire with a plug?

Also it never, ever happens when the engine is cold in the morning, only after it heats up.

Ford dealer diagnosed it as 2 bad COPs and 4 bad plugs, Advance Auto said cylinder 7 misfire... so I'm convinced this is not a tranny issue.

What about a computer flash or reset or whatever? I don't know too much about that, but could this change anything?
Yes the plugs will misfire underload and yes when the engine is at operating temp is typically when you will fell it most often
replace all 8 plugs with motorcraft plugs and give that a try...
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