Long story short my V10 picks up a bad misfire and barely get me home today. I have a scangauge2 hooked up all the time and the codes that come up are P0300 for misfire and P0358 for #8 cylinder. The picture shows #8 thru #10 coil packs. #8 is that black mess on top of the coil. All the rest look fine.so it seems reasonable to change the coil pack without any further testing? Anyone ever seen the top of one of these look like that before?? The truck has about 145000 mile and a lot of rust issues. Thanks!

 

Replace with a Denso or Motorcraft unit.

When were the plugs last changed? Were the boots inspected at the same time?

 

Plugs were changed at about 80000 and it was not fun. Been a long time now so I assume to boots were good or I would have replaced them.

 

Start with a new coil and plug on #8 and go from there if necessary.

 

Your coil failure appears to be due to a high-resistance internal short which caused the coil to heat to a very high temperature before it failed completely. I would replace the plug too, to be on the safe side, or at least check the gap and especially the resistance from the connection to the electrode with a quality ohm meter and compare that to the resistance of a new plug. It is unlikely, but too much resistance through the plug could cause the coil failure you experienced.

The consensus from many previous threads is that Motorcraft coils are the best. I use NAPA coil boots because they are a light grey and it is easy to see if they are discolored from high resistance or blow by from the dreaded loose plug syndrome.

Be sure to clean the plug bore completely before you remove the plug. Debris in the bore will fall into the cylinder otherwise.

BUYER BEWARE! I've found some on-line merchants price coils listed for the V10 higher than those for the 5.4 V8. Same part number, same coil.

Be sure to handle the wire harness gently. I managed to crack or tear one of the seals on mine which allowed water into the connection (even on #3 cylinder in the middle of the engine) and caused a misfire. Clean the seals and use a good quality dielectric grease on them when you plug them back in. Same for the injector connections...

The perfect hell for the engineers who decided to put the back of these engines so far under the cowl would be to spend eternity changing plugs on #4, #5 and #10 cylinders....

 

It will be a couple days before I can get parts but I will reply when I know how it plays out. Thanks for the replies!

 

NAPA claims to sell OEM coils made by Bosch. Does Bosch make the coils for Ford?

 

 

Changed the spark plug and coil on #8 with no real change. Where do I find the EGR valve on this V10?

 

Update. Truck still ran poorly after the coil and spark plug. The codes I was getting from the scangauge11 were really hard to figure out but it hinted at a lack of fuel and that is how the truck acted. I put some HEET in the gas tank and walked away for a bit. A couple hours later after dark I and went for a short ride and it ran fine. My best guess is some water in the gas??

 

Not all V10's had an EGR set up. My 01 never did. As for the lack of fuel, the HEET may have cleaned a fouled injector as well, but water is likely, especially if you live where there is high humidity and run on the bottom 1/3 of the tank a lot and don't drive long distances.

 

This truck normally has less than 1/2 tank of gas and does 8 mile trips to the woods and back. It has been very wet this year also. I did the "out to the woods" trip today and bumped the tank up to 3/4 full and added another can of HEET to it. It sputtered a bit early on but then ran fine. I have no way to prove the HEET is what helped but it sure seems that way. Now the starter has decided to act up and it was new last summer so hopefully it is just a lose connection. The solenoid is clicking so the issue must be after that? It also has a new ignition switch due to an unsuccessful attempt to steal it last winter.

 

Sounds like condensation is forming in the tank. Typical with lower fuel levels, short trips and high humidity. Keep the HEET on hand.

 

The truck seems to be running OK now, that is if it will start. I turn the key and can hear a click under the hood but no starter motor engagement. Do it again and it will fire right up. It seems to be getting worse now with 3 or 4 tries before it starts. Starter is 2 years old but with the solenoid making the clicking noise like it should my assumption is the starter is acting up. The starter is a remanufactured one and I do not remember the company that did it. I am really not looking foreword to crawling under this thing again!

 

At this point it appears that it was a condensation problem and the HEET eventually worked. But wow, if it ain't one durned thing after another!