OK...
the transmission will delay shifting between 2-3. So between 2-3 it will rev higher than normal, then rpm will go down about 2500 rpms as if it were shifting then go back up to about 3000 rpms and then shift and of course it's a harder shift than normal. Today as I was going up a hill the trans kept revving up, then down, up...then down.
It seems to be worse when warm and periodically has similar erratic shifting through all gears. It was perfect before the rough idle, so I'm pretty sure it pertains to the idle. Especially since it's not throwing codes and no CEL.
I checked that spark plug and the seat has no score marks and no tarnishing about 1/4-1/2 " down from the seat of the plug...like all the other ones do.
ARGH...this thing is starting to **** me off. Been an amazing truck the entire time I've owned it and it's my third one. I should have known when to fold em...lmao.

The plugs are OEM motorcraft. I used the high end stuff before and it doesn't seem to jive well with these motors.

 

You might want to rule out a bad cylinder by performing a compression test on all cylinders. If theres any more than a 15% difference between the lowest and highest, you might want to check the lowest by squirting a tablespoon amount of motor oil into the hole and retest its compression. If it increased it momentarily, then you have a piston ring issue, if it didn't make any difference then its a valve issue which only a leak down test would reveal which valve it is.

Additionally, if your technician buddy has an oscilloscope, he can use that on your ignition system to identify exactly which cylinder is having the issue by looking for uneven voltage spikes in the scope patterns of each cylinder, which can tell you if the cylinder is running too rich, too lean, has vacuum leaks, low compression, bad plugs, wires and more.

Even hooking up a vacuum gauge to the motor while it is idling can reveal allot.

As greasemark said "Engine first"

Just my 2 cents...

 

Well, I'm just gobsmacked a bit buy this. Since I'm not there and can't do my usual "seat of the pants" or "on the drive-in" road test, I can't rule out that they either are or are not connected; tough experience tells me that they probably are not related. The only thing i could say for sure is if the engine isn't making as much power as it should, then the trans won't have a chance to shift right.
However, I know you've been working on it. So how goes the re-threading of the plug hole?
And from what I've read, I'm more concerned with the trans. So, read this disclaimer: if the engine is not producking the power it should, none of what I say from here on out will not matter. SO:
Is this the old 4/5R55E problem of the "slide-bump" shift? This is where the trans will either take a longer time shifting or actually slip outright, then firmly lock into gear and not slip after that.
I'm also wondering if this is a hunting problem; that's where the transmission is shifting back and forth between a gear and the next adjacent gear to try to cover for an engine that isn't producing enough power (see what I said about making sure the engine is fixed first?). But, is that what you mean by erratic shifting?
I'm sorry if I'm not much help, but I need a bit more info to make up my mind (what little bit is left).
And don't worry; I've never known when to sell them; I owned a Mustang once that I loved, but it was the biggest piece of junk I ever owned; that that INCLUDES a Chrysler!

 

I am taking it to a mechanic tomorrow to have him correct the spark plug conundrum. Erratic meaning, not shifting normal. I am convinced it's related to the running just because they happened simultaneously. I believe I can hear the compression coming out of the spark plug hole (no joke). I'm not sure if I should have him try to rethread the hole or just have him helicoil it...thoughts?
Still no CEL and gas mileage is more than ****ty. I feel like a clock watcher...just watching the mile to empty tick away like seconds on a clock.
The shifting is the only issue really, when it's in the appropriate gear for the speed I'm traveling...it's smooth and you'd never know there was an issue.

I will have him check compression during the healing process of hoping resolving the infamous spark plug crisis.

 

Be careful on what shop you take to even the best mechanics have trouble repairing someone else's f$%#up. and it can get really expensive. it might be better off just replacing the head if a man or woman can't do the job right. the shifting is related to engine not producing enough power for the speed you want to travel. and being that everything is controled by the damn computer it is gonna act up.

 

DO NOT HELICOIL THIS PLUG HOLE! The helicoils tend to either work out or seize in the plug hole, and the usually get blown out. It's totally normal to hear leaking compression, also (that's the driveability thing again).
There are two other options for the plug hole: tapercert or the other kind of inserts that you tap and then epoxy in (not kidding, and it works like a charm on the 4.6 and 5.4 that blow plugs out). I just can't remember the name of them.
Getter fixed up. I'm sure she'll run like a top!

 

I'm glad you are all sharing because I was starting to think towards heli-coil.
If you can remember the name of that epoxy, that would def be something to consider and I need it fixed yesterday cause it's my only vehicle.

Can I get the "tapercert" from oreillys or autozone parts store.

 

Wow? , My apologies for stepping in. By all means, proceed on...


@ only1bigdaddyo (The computer controls the transmission, but it uses inputs from the engine as well as some sensors on the other drive train components. Yes, I do somewhat suspect one or more of the transmission clutch packs might be worn so far that the piston might be traveling beyond its bore and losing its hydraulic charge, then the return springs will send it back to its home position. Thus the partial engage then disengage symptoms. However, this does not explain the engine issues...) <-- my -2 cents worth...

 

Oh, don't worry. You always have to get the engine running properly to get the transmission diagnosed; Ford was a very fertile car maker for trans. problems.
As far as taper certs go, do a google search; I don't thingk you'll find it at O'reillys, but you never know.

 

@greasemark...is that "cert" called "time sert"?