Thanks to everyone for their information - my miss problem on my '99 F250 is gone, but not without a lot of work. I took the truck to an independent shop this morning and he put it on a Snap-On scan tool but it gave no errant readings. He indicated his experience has shown that many '98 and '99 fords -if they give a misfire reading - will show "random misfire" and not indicate the specific cylinder. So... I spent a large part of the day changing plugs and checking my coils with an ohm meter. I checked primary and secondary resistance on each coil with resistance being consistent all the way around with the exception of the #5 cylinder which showed large fluctuations in secondary resistance as I put pressure on the spring with the end of the probe. I have a feeling there was a problem in the spring itself probably where it attached to the coil. That might expalin why the truck idled smooth but had serious stumbling on acceleration. So I changed all the plugs and the #5 coil and now it runs as smooth as silk. As everyone agrees, the number 4 and 8 plugs were tough to get to (#7 wasn't easy either). I was able to get to the 1-4 plugs without removing the fuel rail, but had to loosen the two screws on the drivers side rail to maneuver the rail aound to get to the # 7 and 8 plugs - there was no other way on this 250. There was a great thread on this side posted by Moderator Dave to help with steps necessary in changing the plugs. The information was very helpful and right on target. As indicated, attach your plug socket to your extension with electrical tape or by welding or whatever way you want or you'll be trying to dig the socket out all the time. One other suggestion, it would be helpful to place bright colored tape on ends of hoses and electrical connections you moved or removed so you won't miss them when you start to reconnect. There could be quite a few. Total job time - 4 1/2 hours.
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i just take the rubber bushing out of my sp socket on install and i take the drivers side fuel rail up off the injecters to move it out of the way my first time took about 3 hours

 

Went through the same sort of thing on my '99 V10. Code reader only gave me a "multiple cylinder misfire". Ohm meter readings showed no annomalies.

So . . I took the rig to my trusty local mechanic who hooked up his Snap On MT-2500. After fiddling around for over an hour couldn't find a thing, and told me to take it to a Ford Dealer.

For what it would cost at a Ford dealer, I figured it would be better to invest those $$$ in a proper scanner. Got an inexpensive Auto Xray EZ-Scan 6000. It was able to read manufacturer specific mode $06 data, which includes the misfire counters for each cylinder. With the EZ-Scan 6000, at a fraction of the cost of a Snap On, it only took five minutes to pinpoint the defective coil. Replaced #5. All done!

 

I found a good reader interface if you have a laptop or computer in your garage.
obddiagnostics.com sells it for less than 100.00 with free dos / windows or mac software.
It works with all three protocols. It will pull up the extended codes. It has the codes listed in a help file. It also does realtime monitoring of engine functions either in number
or gauge display.. I couldn't beat it for twice what he asks for the built unit...(there is a kit that is cheaper)

Duane