So newbie here again. With another question for the experts.

Recently the 2000 Excursion v10 started to drive rough and I think I have a misfire going on. Starts to show up around the 45-55 mph range while driving down the road. Also getting that putt putt off the exhaust pipe. A family member who has a F250 mentioned just unplugging the ignition coils one at a time to see if a coil is gone bad. Says that if it's a bad coil there won't be a difference in the way the engine idles but if its a good coil then it will idle rougher.

Its been a while since I've had a vehicle I can work on and not be concerned I'm gonna mess up the computer system.

While checking out the coils I found a few that appeared to be loose and the screws didn't appear to be secured all the way. I really don't know what I'm listening for if I start unplugging them one by one.

I did come across one coil that the bolt appears to be broken off and that the coil isn't bolted down. Just sits there. I'm not sure if that is my problem and its getting back pressure and pushing it out some to cause a misfire or if its something else or a separate coil.

So I guess this is a two part question.

a.) how do I drill out the broken bolt? I think if I had to guess from looking at other ones it might be a M5 bolt. Anyone confirm that?
Do I use a screw extractor? if so what size? Haven't found one for that small a Bolt yet. Quick search leaves me at m8 or bigger.

b.) what things can I check to try to sort out this misfire?

Thanks in advance!!!!!

 

I can help with some of your questions as I have done the plug & coil replacement about 9 months ago. Use Motorcraft plugs & coils. Less headaches than using aftermarket parts. The back two plugs are hard to get to but doable. I put some anti-fatigue mats that I stand on in my shop and laid them across the engine. Others have used blankets and others have used the little giant ladders. Be careful when you pull the coils & boots off. On one of mine the boot broke off and left about 1" on the plug. You can't get the sparkplug socket over the boot to take the plug out until you remove the broken boot off. I got a slightly bigger socket (not the hex socket) and was able to get it on the broken boot and twist it off. It took some time but I was finally able to get it off.

There are several threads on here about changing the plugs & coils. Find and read them to get tips that will help you.

The bolt size is M5 x 30 metric flange bolt fine grade dog point grade 8.8 head size 7mm. The Ford part number is W711062-5437.

 

I would suggest getting a OBD2 cable and downloading Forscan to your laptop/tablet etc. You can use the Mode 6 scan to tell which cylinders are misfiring, even if it is not enough to throw a code.

If you are running a tune, put it back to stock before using Mode 6. With my 5 Start tune mode 6 didn't work.

 

How many miles since the plugs or boots have been changed?
If the spark plug boots are original they are probably aged out by now, they can be arcing right thru the wall of the boot even if looks fine.
The boots can easily cause a misfire and it takes a lot of misfires before a code is posted.
The boots can be purchased separately, Denso 671-0001 RockAuto $35.
The coils will far outlast the boots.
X2 on replacing with Motorcraft plugs, SP479.
Be careful pulling the COP connectors, they are getting old and brittle, but are available if the locking tab breaks.
Inspect the coil casings, a crack in the casing or connector section will definitely cause a misfire.
If the plugs and boots are old and need to be replaced anyway you could change those out and the misfire may be resolved.
Don't let this go too long, the fuel getting to the cat from the misfires can damage it.