Coil on plug # 6 on Ford V10

Probably not related, but my 5.4L V8 1999 E250 had number 6 coil pack go at 74K miles, had the pack replaced and all the plugs and wires replace while they were in there. At 76.5K miles number 8 coil pack went out. Decided with the labor to work on an E250 I had them just replace all 7 remaining. hopefully that takes care of the problem for a long time. Not cheap having it done at Ford but that was the convenient place to do it.

On my 02 V10 it was #3, I had to change it 3 times in 185,000 miles. I changed all the plugs at 100,000, and changed 2 or 3 other coil packs during the time I had it, but #3 I changed 3 times.

Our 2008 e450 started stumbling this summer coming up i5 from California , I changed the plugs and was running out of time for another trip. Took I it to the dealer $375 for one coil and I could have gotten all ten for 250 on amazon, this was at 60k, and I needed it so I was on with that.

I have a 2004 F250 Super Duty V10 and just had #6 coil pack replaced at the dealer and my motor was running the same. This was after changing fuel filter and mass air flow sensor which temporality corrected the issue. Local mechanic tried the you need a tune up which I had alreaady changed the plugs 2 years ago at the dealer which tested all the coils then. And I took it to the dealer after being told it needed a tune up. Simply due to if they needed to replace a plug they could do it. As with aluminum heads it would be on them if the screwed uo installing the plug. All that it ended up bei g was tthe #6 coil pack. It runs great agin and has 130k on it.

I have my doubts that #6 has any design errors above any other cylinder, I highly suspect that it is more like a coincidence that folks are pointing to #6 more often because they are POSTING the "results" that they found.

Good chance that there are just as many other folks who DIDN'T post (unreported) about #6 evening out the odds..

Pretty much with a V10 you have 10 coils/plugs to figure out which one is the problem child.. So, a 1 in 10 thing IF it is only 1 if you are lucky.

I had one 5.4 go 200,000 miles before experiencing a COP failure and another 5.4 which barely made it 100,000 miles before a COP failure.. Don't remember which cylinder.

I can tell you this, don't buy the generic COPsm they are good for troubleshooting but I didn't have them last more than 6 months before random misfires.

You can buy a complete set of generic COPs for troubleshooting ($60 for 8) and when you find the bad one replace it with a OEM one ($60 for ONE).

As far as popping plugs, I have had 5.4s from 97, 2003, 2006 and combined mileage of almost 500,000 miles and never popped one.

The reason for no popped plugs, you MUST use a TORQUE WRENCH and TORQUE THE PLUGS TO PROPER SPECIFICATIONS FOR THAT ENGINE YEAR!!!!

You can not rely on hand feel torquing like everyone did on iron heads, you will either overshoot and damage aluminum head threads or under torque and have the plugs work lose.

If you did not use a torque wrench, please reconsider..

Hopefully it's not just a symptom of a bigger problem. I had a `13 F150 with the 5.0 V-8. It started running rough and would occasionally throw a CEL. I did everything I could to the point that I had to take it into the dealership for them to check it out.
I had 1 for sure misfire and an intermittent misfire on another cyl and was loosing compression in one cylinder. They wanted to replace the whole engine, and an independent shop said they could just do a valve job but is was still gonna be expensive. $11K at Ford for a new engine, $5K+ for a top half rebuild. I figured the truck was 6 years old and 125K miles so I traded it off.
Hopefully yours is truly just a bad coil pack

I have the same year V10 on my 2003 class A and was not aware of #6 coil/plug going bad. I had to replace coil pack on #8 at around 85k miles.

#6 plug is the front plug on the driver's side. If that is a common problem on Ford trucks (F350) I would suspect an air flow problem. On my class A there is nothing blocking airflow to the engine since there is more room to put the coolant tank, air intake, etc.

opnspaces wrote:
Only a guess not knowing the position of the #6 plug. Something, either the airflow or maybe the EGR tube is putting more heat on the #6 coil pack than on the other coil packs. This causes it to degrade faster than the others.

Older low revving motors used to get a problem with rear head oil drain holes. This would cause the engine to perform as described above..
the head would overfill on oil and seep into valves. cause plug fouling. Just an idea from an old guy. hope iy helps.

Thanks for the suggestion. I will check that out. In looking at it today there is a weird gasket section sticking out of the block that the head does not cover. No leaking and its been that way for the 4 years I've owned it. Just looks like a design engineering error.

Only a guess not knowing the position of the #6 plug. Something, either the airflow or maybe the EGR tube is putting more heat on the #6 coil pack than on the other coil packs. This causes it to degrade faster than the others.