My F-150 has been giving me fits. It got so it would missfire going up a hill. Idle fine, around town it ran fine, going down hill fine, drop the hammer from a stop and it wouldn't miss a beat. But going uphill warmed up with the cruise on it was a wing and a prayer. Didn't missfire enough to set the CEL or throw a code. Figured it was a coil but they are $40 a pop for parts store stuff and I have 8 of them so it would get painful kinda quick to start throwing coils at it. I could take it to a dealer and pay them whatever they get for diag but where is the fun in that? So I do research, download Forscan on my laptop this past weekend (for free.99) and after acquiring a WIFI OBDII adaptor I start poking around... #5 had a missfire 3.32% of the time, minimum threshold is 23.04% to throw a light if I am reading it right. I throw a coil on #5 and it runs perfect. The coil I replaced was original with 180k on it so it didn't do too bad. It had corrosion on the contact so the coil was probably ok but it was overheating because of the increased stress because of the bad connection. It was really infuriating though because I thought the point of this electronic stuff was to make diagnosing easier...
Then I crawl under it while I have it in the shop because something has been feeling loose in the front end, the newest balljoint on the truck (a 2yo Moog) is shot which is neither here nor there with the roads the truck sees... potholes, washboards (or corrugations depending on local vernacular) Also notice while I am under there a CV boot is torn so yay... a new adventure awaits on that.
The '85 Ranger I had been driving in the mean time has one easily to get at $15 coil that requires no special tools to change and not a single cv boot to be found anywhere...
My '85 has a carb (with an electric fuel pump) and I really have no complaints, the new FITech type fuel injection setups look mighty tempting for better off camber operation though. If they existed when I originally built the the truk almost 9 years ago I probably would have gone that route. (Holley and others had TBI kits but they were really pricey back then) Being a flatlander I did a couple mods I saw on the internet to my Edelbrock before we went out to Ohio for a trail ride last fall and I was really quite impressed with it.