2005 Ford F-150 ignition coils

Tiny
JPDEP
  • MEMBER
  • 2005 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 115,000 MILES
I recently changed the plugs in my 05 f150 5.4l. Now it is running worse than before I changed the plugs. Would the ignition coils and boots need to be replaced also? I cleaned the boots and springs in them and placed fresh dielectric gel on them. I don't know what I did wrong.
Monday, October 27th, 2014 AT 4:17 PM

9 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
What I have seen happen many times is the boot goes bad and the spark is partially shorted out. This results in a misfire. Tell me, is the check engine light coming on or flashing?
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Monday, October 27th, 2014 AT 6:27 PM
Tiny
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Yes. It went off initially when I changed the plugs but came back on shortly after. I was able to drive it long enough to take it to an auto store to have the codes read. It said there was a problem with the coil. That's when I removed them and cleaned them. The light came on again but I haven't been able to drive the truck back to have it read again. It has no power and stalls.
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Monday, October 27th, 2014 AT 7:22 PM
Tiny
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I'm just thinking that it should've been running just as rough before I changed the plugs if the coils and boots were bad too.
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Monday, October 27th, 2014 AT 7:26 PM
Tiny
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We need to have the computer scanned to determine the affected cylinders. That way we can focus on where the problem is coming from. Can you access a scanner? Something is telling me that the boots on the coil packs are bad and they are arcing.
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Tuesday, October 28th, 2014 AT 5:00 AM
Tiny
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Yes. I changed all of the plugs, boots and coils but now I'm having the same original problem (hesitation and skipping when excelerating) and I also notice shuttering when excelerating at about 50 MPH. What did I do wrong?
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Monday, November 3rd, 2014 AT 5:52 PM
Tiny
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I also took it to an auto store to have the codes read and it basically said the same thing. Misfires in cylinders 2&3 and other fuel performance and injection probable causes.
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Monday, November 3rd, 2014 AT 5:55 PM
Tiny
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Is it possible for you to get me the codes they retrieved? As far as the problem, I doubt you did anything wrong. The problem was there before you did the work, correct? Have you removed cyl 2 and 3 plugs to check if they are properly gaped? If not, do that. Also, pay attention to the plug to see if it is wet with gas or is black.
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Monday, November 3rd, 2014 AT 6:40 PM
Tiny
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The codes it retrieved were P0300, P0301, P0302, P0303. No I haven't observed the problem plugs yet. This was just today. I did not have to gap them because they are the type of plugs that have the outer metal shell that forms a hood over the ignitor. (The ones that are notorious for breaking). Or are they still able to be gapped and I dint do it?
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Monday, November 3rd, 2014 AT 7:06 PM
Tiny
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I think you should pull them and inspect. Something may have gotten on the end and causing the problem. Plus, I would like to know their condition. Are they wet, corroded.
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Tuesday, November 4th, 2014 AT 8:46 AM

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