Hi All,
I got an '01 v10 Excursion a little over a year ago to use as a tow vehicle. Overall it has done a good job and is nice to travel in. Plenty of room for the family and dogs. Handles my 30ft bunkhouse with no issue.

Now for the bad (and the purpose of this thread). It had misfires issues when I got it. Enough that it would throw codes etc. I replaces all the plugs, COPs and damaged COP connectors. This got rid of 95% of the misfire issue, but I still have a slight one. Not enough to throw a code, but I can feel it shudder in low rpm high load situations. I confirmed this by using Forscan and Mode06 to ID the cylinders. It is consistently cylinder 2 and 7 (right across from each other). I have swapped plugs around as well as COPs with no change. I also replace the injector electrical connectors since the previous owner had zip tied them on.

The only thing left I can think of is that the #2 and #7 injectors are bad. My next step was going to be to swap the #1 and #2 injector to see if the misfire follow it. I haven't messed with injectors on the v10 before. It looks like it is just a couple of bolts on the fuel rail and then the injector pulls out. Most likely seated with an O-Ring of some sort. Am I thinking correctly? Anything to watch out for when swapping the injectors around?

Also, if it isn't the injectors, does anyone have another idea on what it might be? Is there something electronically that it being the #2 and #7 cylinders would point to? Do they share a ground or wiring of some kind? I am kind of at a loss on this one.

Going to post over in the v10 forum as well.

 

Just a thought but I’d confirm fuel pressure is in spec before I swapped injectors.

 

Buy a pack of o-rings first. Don't ask me how I learned that...

I'd suggest a dry/wet compression test before swapping injectors. Might be a base engine concern.

 

Any specific type of o-rings, or just a variety pack from the automotive store?

 

Just look up the ones for your engine and buy a pack.

 

There are O rings on both ends of the injectors. Make sure you get a pack that comes with the tool, makes installation way easier.

 

After checking the injectors i would clean up the PCM plug/pins. The 2/7 coil signals comes from two pins close to the outside of the PCM and next to each other. It wouldnt be unheard of for corrosion to get in there.

 

I was going to go ahead and pull the PCM to clean up the connection.

Found it under the dash. As far as the engine side it looks like the plug is under the brake MC/Booster. In the videos I watched (couldnt find an Excursion specific one) they all show one 10mm bolt to loosen and then you can pull the plug. I can't see the really well, but feeling around the plug feels a lot bigger than the videos and I feel 3 bolts.

Am I missing something?