# Bad miss while driving



## dieselboy01 (Jan 18, 2011)

I have a '00 F-250 SD with the 5.4. I was driving down the hwy around 60 mph and the truck started to shake and sputter. Got her home and found the #5 and #7 coil pack cracked. I replaced them both and went for a spin, the truck ran good for a few minutes and then back to a bad miss. I checked and I have power going to both coils, all the connections are tight, any suggestions would be greatly appreciated.


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## GSS LLC (Jul 7, 2012)

May have fouled a plug.


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## Wilnip (Oct 4, 2011)

Put a scanner on it. Even though the check engine light may not be on, the scanner should tell you what cylinder is misfiring. You may have a 3rd coil that went bad, or plug, or whatever. At least you will know where its coming from.


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## dieselboy01 (Jan 18, 2011)

Ill try a scanner, the plugs have around 15k miles on them but one could have fouled. I was doing a little more reading on this problem and it could be a few sensors causing this "miss" also. Cam, crank or throttle pos.


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## dieselboy01 (Jan 18, 2011)

I scanned the truck and I came back with a #2 miss fire, #5 &#7 secondary coil fail, I replaced the #5 &#7 coils, and have power to them. I found the #2 miss fire is a generic code that can be cam/crank sensor or tps. any more ideas before I throw in the towel and bring the truck to my mechanic?


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## wewille (Jan 20, 2009)

Where in southern wi are you?


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## dieselboy01 (Jan 18, 2011)

I'm in Wind Lake.


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## Wilnip (Oct 4, 2011)

I would try replacing number 2 coil with another coil, say coil from number 4 and see if the miss fire moves cylinder four. At least then you would know if that coil was bad before you start replacing sensors.


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## 91AK250 (Nov 28, 2007)

i ended up just replacing all the coils on my V10. they all had corrosion and i figured might as well just get it over with. did plugs at the same time. that was about 19k miles ago.


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## Holland (Aug 18, 2010)

Wilnip has the right idea. Try that and get back to us.


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## dieselboy01 (Jan 18, 2011)

I unplugged the #2 Coil and the miss got worse. I think that coil is good then.


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## brad96z28 (Aug 21, 2005)

Secondary coil codes are probally from unplugging them with the key on. Clear codes see what comes back first.Is is misfiring at idle or only while driving?


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## Holland (Aug 18, 2010)

Best way to tell if its good or not is to actually swap it with another cylinder and see if the miss moves with it. Not saying its bad or not, but i wouldnt rule it out till i actually moved it.


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## dieselboy01 (Jan 18, 2011)

Ill try that this weekend, Its raining pretty good out right now and I don't have a dry place to work. The miss is at idle and while driving.


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## Milwaukee (Dec 28, 2007)

Did you know that worn out spark plugs will strain and kill coil packs. If it had 100K miles on it. Time to replace them with Motorcraft spark plugs.

I deal with those many times on 5.4L that been sat alot. Had 2 that never show codes but miss/ sluggish. End pull all coil packs and notice there green corrosion in spring.

I just clean them and add diegrease to tip of boot and little in coil pack where spring go in.

Have you wash engine recently? Don't be surpised if bottom spark plugs is full of water.


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## dieselboy01 (Jan 18, 2011)

The spark plugs have less then 15k on them, Installed last year by a Ford truck mechanic. I have never washed any of my trucks engine bays, 5.4, and the 6.8 hate water.


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## Plowtoy (Dec 15, 2001)

dielectric grease the end of all the coil boots. Maybe they are carbon tracking?? The C.O.P.s are notoriously bad on the early 4.6, 5.4 and 6.8 engines. Seems like they got better over the years


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