The other day, I did the dreaded spark plug and ign. coil change on the 2006 F-250.
All in all, it went well, and I declared a victory.
Upon driving it more, I found that when I pushed in the clutch, and came to a stop from 50mph or more,
it'd idle down to 250-300 rpm, not quite stall, then 'think about it for a bit', and come back up to 750.
I figured: Hmmmm,,,,,, this will not do.
So I got to researching some more about why it did that.
I found all sorts of things it could be, and needed to be changed. Various sensors, the throttle body,
all sorts of things that I knew hadn't just died because I changed the plugs & coils.
-------And some of them even cost less than $200.
I finally found an old car forum post about if you change certain things--- it has to 're-learn' how to idle.
Oddest thing I ever heard. But I had unplugged the big wiring bundles to be able to reach in behind them.
According to the truck--- that counts as changing certain things.
I found out you have to 'drain' the forever memory in the computer by taking off the neg. battery cable,
then touch it over to the (+) post for a minute.
After that, you have to start it, and let it idle for 20 minutes, then drive for at least 30 miles so it can re-learn
how to idle and adjust itself to your driving habits. I've read the shop manual cover to cover, and never saw that.
After working on carburetors and breaker points ignition, with a few GM HEI ones thrown in,
that was the oddest thing I ever heard of.
But I did it like it said, and that fixed it.
Now I can look out the windshield instead of staying focused on the tachometer.