2001 Super crew 5.4. Seems like everytime I crank it up it idles fine, I ease down the driveway our out of the parking lot and when I drop back to idle it kind of "shutters" and rpms bounce around 500. I give it a little gas 1500rpm or so and it clears right up, or if I drive down the road it is fime. Most of the time it is only the first time it comes back to idle after being cranked up, I won't have a issue again until shut I off. It doesn't seem to matter whether it's hot or cold, or how long it has been shut off.

Any ideas? No codes concerning it, the only code is a p1635 (something about tire/gear ratio out of spec)

 

https://www.autocodes.com/p1635_ford.html

It may be a sticky IAC, I'd remove it and clean it - spray it out with WD-40 and work the plunger with a small screwdriver. It also wouldn't hurt to pull the throttle body and clean it, also clean the MAF sensor.

 

I cleaned the MAF and installed a new air filter yesterday.

IAC, that's kinda on the backside of the throttle body right? I'll pull it some time and see what it does. would it be safe to clean it with MAF cleaner, or throttle body cleaner? I have a can of both or is WD40 the best?

 

You need something like WD-40, something that has some lubricating properties.

 

yes its more on the passenger side.

You can clean it with some carb cleaner/ throttle body cleaner....but it is a bit harsh. WD40 cleans well and has enough lubricant to it to help keep it functioning. If you use carb cleaner, dry it out well after it is all clean all the while working the small plunger/rod back and forth and then add a some light lube and work it back and forth again before re-installing.

Not sure how well MAF sensor cleaner would do on heavier deposits.

 

Thanks, I'll do that some time this week.

 

Some points are being missed here.
At 1500 rpm you open the throttle beyond the IAC open area and it becomes less in airflow control.
At cold starts the IAC can stick from Gum and dirt then free up or it can go the other way and be free when cold and stick when engine heat affects it.
Also there is an air bleed internal to the solenoid inside the can housing.
You cannot clean that bleed hole with out disassembly that will reunion the part.
Only part that can be cleaned is the spring loaded pintel valve in the outer housing.
The IAC plays a large part in overall engine operation especially on cold starts and is closed on deceleration and maintains idle under all conditions.
When it's operation fails you have cold start, stalling and idle issues.
Good luck.

 

I'll pull it apart and see if I can clean it up good, if not I'll replace it.

 

Alright pulled it off, it seemed like the plunger was stuck. I tried to open it prior to using WD40, it opened but made a "Suction" release sound when it finally opened. After soaking it with Wd40 it moves a lot more freely for sure. Getting ready to throw it back on.