I know the earlier models 1999-2001? had a TSB for idle issues associated with the connector/wires to IAC or TPS. It had to do with splicing in a new connector so the wires were longer because the tension on the shorter wires was causing connectors to lose connection.
It was a $75 part.
My 2000 had a lot of issues with idle and every 6 months or so I would have to replace IAC and it would work for a while and then start high idling again. Through a lot of trouble shooting it was actually me disconnecting and reconnecting the connectors that temporarily fixed issue.
Me being cheap, I wasn't about to spend $75 on a crappy looking fix, so I took the IAC and TPS connectors apart and hosed off each with Electronic parts cleaner and while the connector was wet, I connected and disconnected several times to help clean out the corrosion. Once connector was dry, I used dielectric grease on the connectors to prevent further corrosion. My truck has been high idle free for over 6 years now

 

Got the truck in the garage tonight.

I replaced the IAC but that was NOT what I disconnected with no change. I was disconnecting the TPS with no change. When I disconnect the IAC the truck stalls

I cleaned both connectors and put diametric grease on them. Started the truck up and it was ar 2100rpm

As I was hooking the scanner up the idea slowly dropped down to normal

 

I have 1% AND 2% on my LFTRIM AND SFTRIM

Idle is at 1050rpm

LFTRIM SAYS 11 to 13

SFTRIM SAYS -2 to 2

 

OK, good idea to have posted some fuel trim numbers. Were these numbers averaged for both cyl banks, or if for any one cyl bank, which one is the data for???
LTFT says the computer is having to Add fuel over time to compensate for what it's determined over time to be a lean trending air/fuel mixture. Could be lazy/slow switching O2 sensors, dirty fuel injectors, clogged air filter or air intake, clogged exhaust, misbehaving sticking open, or worn not seating closed PCV valve, or loose leaky hose or fitting to it, intake manifold vacuum leak, brake booster vacuum leak, emissions system vacuum leak, in cabin heater/ac control system vacuum leak, the list goes on & on.
SO, measure the STFT, LTFT & upstream O2 sensors switching range & speed on Both cyl banks, MAF sensor info & lets see if you can narrow your suspect list down to a particular cyl bank, or if it appears to be an over all problem that would suggest looking upstream at a dirty MAF sensor, clogged air filter, or air intake, or dirty fuel injectors if both cyl banks seem to be trending lean over time.

 

My scanner only goes to 99 So I lie to it and say it is a 99. I dont see any listing for left or right bank on the O2s

Exhaust is good, I actually just punched out the "collector" cat
O2 sensors are maybe 2 years old
Air filter is good
I run seafoam periodically in the fuel for cleaning purposes

I an check the MAf but being intermittent, I cant see that being the problem

I am leaning more towards faulty wiring

 

"I run seafood periodically in the fuel for cleaning purposes"
Don't the shrimp plug up the fuel filter???? LMAO.......damn autocorrect!

 

Consider coming by the inexpensive but in depth informative ELM scantool running FORScan or the like software that's tweaked for Fords, to the viewing device of your choice, like discussed here https://www.ford-trucks.com/forums/1...-scantool.html & have it take an in depth look at whats going on with the fuel control devices in Both cyl banks & idle speed control to see if it can narrow down your trouble shoot.

Make sure the Basics are right. Under Load battery & alternator voltage are in spec. Battery to engine & body grounds are clean bright & tight. Perform a wiring harness wiggle/thump test at the IAC & computer harness & electrical connectors, to see if you can induce it to act out. Make sure you have B+ to the fuel injectors at KOEO, so they are squirting right, if the computer grounds are clean, bright & tight & the injectors are clean.
A 20 oz dose of Techron Concentrate Plus in the tank at the pump before filling with Chevron, Texaco, Caltex, or now Shell, (all of which have some PEA in their ad pack), will raise the treat rate 10X above pump gas alone, so can tidy up dirty fuel injectors often in one treatment. It can also decarbon the intake valves, piston crown & combustion chamber.
The IAC is a common problem part in idle speed woes. Cleaning the IAC often doesn't last, it didn't for me on the 99 Ranger, but was a good trouble shooting step before replacing mine with a BWD. Motorcraft, or BWD are recommended replacements if it comes to that.
More thoughts for consideration, let us know how it goes.

 

I'll have to see if I can get a cartridge to go up to 04 for the scanner

 

The IAC can act out & not set a trouble code, so don't take off your suspect list yet.

 

I replaced the IAC yesterday with a motorcraft one. SAME problem

 

OK, so the other tests proved naught & you were left with replacing the IAC, or have you not completed the other diagnostics???

 

I did the shake test on the wiring, it did nothing. I also cleaned and dielectric greased the IAC and TPS plugs

Grounds are good.

I have 13v at and idle

 

Ok, 13 volts at idle is low, it should be something like 14.7 volts, so rev the engine to about 2-2.5K rpm & measure the voltage. Then load the system by turning on heavy electrical loads, like all of the lights, like head, fog, dome, blower motor on High speed, cigar lighter pushed in & see if the alternator regulator can keep the voltage up under load. If not, with your multimeter perform Under load, end to end voltage drop tests on Both battery cables & across their electrical connections on Both ends of those cable runs. If they check out ok, check the output at the alternator & the battery cells SOC with a hydrometer.
If you don't have removable cell caps, perform a open circuit voltage test with your multimeter after the battery has rested over night & before you start the engine.


If you are in doubt on how things are testing out, run this puppy by your favorite autoparts store for their in vehicle electrical system check up. It can trouble shoot the battery, alternator, battery cables & their connections while in the vehicle & properly done can give us a good idea of our electrical system health.


Since in the past you've gotten positive results replacing the computer, did you include its firewall electrical connector in your pin/socket/wiring inspection for damaged wiring, poor wire crimp, pushed back pin/socket, bent pin/mashed socket, pin/socket corrosion & a wiggle test on that connector while the engine is running, to see if you can induce the problem????
Are the computer grounds clean bright & tight?? Did the replaced computers show any signs of having had water on them???

 

I have not checked the ECM plug. Maybe today.

I was out plowing all day yesterday with the truck