Just replaced the IAC this morning. Here is the gamut.
I flew out to Delaware last week and let the truck sit at the airport lot for the week. I had changed the COPs(very happy BTW ty to Global) the weekend prior to leaving. Did a lot of driving, no misses, she was running great.
We had a cold snap here in Houston Sunday night. I got of the plane about 12:00 mid night. I drove the truck home, idle was great, no misses. When I got off the freeway and came to the stop sign she died. I put her in park and she started up perfectly. Put her in drive and I had to give her gas to keep from dying. Essentially she is searching for idle when I engage the transmission. Naturally I decided to replace the IAC as I think I have not replaced it before. There is NO CEL btw. I replaced the part this morning and I still have the same problems. Rock solid, steady idle in park and neutral, but as soon as I get to drive she drops to 300+/- rpm and begins searching. If I am parked and shift between neutral and drive, it goes from perfect idle to dies immediately. The exhaust system is entirely new. I haven't found any vacuum leaks. The EGR valve and regulator are new. I have a fresh tank of gas and the fuel filter is fairly new as well. The MAF is new and I am using the factory induction with an OEM filter.
Any ideas my friends?

 

I read about the Tranny Filter coming loose and this may cause the issue I am having.......
bump

 

That's a new one to me, I'll have to search around for that. Maybe it has something to do with the programming?? Did you try switching back to stock and seeing what happens?

 

I may do that, but I seriously doubt this a tune related issue as the vehicle runs and shifts normally, it is only at a stop under load (in drive) that is wants to die.
I didn't find any sort of vacuum line from the tranny to the motor, but I didn't look super hard yet. I am going to drop the pan this afternoon and check the filter.
I'll let you know what I find.
Still waiting on Bluegrass, Jbrew, Built54, etc... you smarties to chime in here as this is an interesting issue I am having.

Thank you jester for your post too.

 

I know it's the holidays, I am just keeping this at the top of the list.
Thanks all.

Motor will die when going from park/neutral to drive.
Motor will stumble and can die when rolling to a stop; however today she has not died coming to a stop. The RPMs will drop to about 300 RPM, but come up fairly quick and maintain a steady (but not smooth) 650 to 750 (i am going by the tach). IAC replaced yesterday morning. It probably didn't need to be but the old one was original I believe but still working fairly well. With the new IAC the park/neutral idle is fantastic, smooth as glass.
No CEL and I have driven 50+ miles. In this vehicle, the CEL always comes on (if there was a problem) at 28.7 miles into the new drive cycle.
Just trying to give all the info I can. I can't find a leak and I know all the infamous ones there are. I read there may be an issue where the transmission filter comes unseated from the tranny and under load can cause this symptom, however shifting seems very good to me. Truck drives fine, no performance issues either.

 

C'mon guys!!! Where are my geniuses when I need you!
I just went by the tranny shop and they seriously doubt my tranny is causing the problem due to the fact that it performs flawlessly when I am cruising down the road. I cleaned the TB a while back (30,000 miles ago or so). Is there anything int the TB that can go bad or where out and cause this issue of dying when I put her in drive?
WTF
Gas Mileage is normal
Performance is normal
hmmmm...........................

 

do a search for "Rough Idle"....a post I had a couple of years ago

Sounds like your EGR ports are clogged., which requires you to tear everything down to the intake runners (it's really not too bad, I did it for the 3rd time in 3 years last week and had it back and running in less than 2 hours)

 

here i found it. give it a read

https://www.f150online.com/forums/sh...h+idle+problem

 

It's a bit unusual after replacing the IAC to have this situation.
Let me ask; if you throttle up to just the 6 or 700 rpm that you would normally see in gear, does the motor want to pull the truck harder than you remember?
If yes, it's a trans problem. The lockup may be engaged when it's not supposed to be or ?. The shifter might be flashing or on if this is an issue.
Might even involve the trans selector signal to the PCM.
Check for a code that may involve the trans.
Just a guess at this point.

 

Thanks guys. I had that TB cleaned not more than 30,000 miles ago but I may pull it again tonight just for grins. Bluegrass I do not feel like the truck is pulling any harder other than normal at the 600 to 700 RPM range but I will give her a test around lunch time. The OD light on the stick has flashed in the past, but that was many many moons ago and since I have had the tranny serviced it has not flashed. In fact the switch works like a champ. I dropped the tranny pan yesterday and the fluid was fine, and the filter was in place. I topped the fluid back off and same problem. I went to the tranny shop near me and they are leaning towards the engine, a possible throttle body issue. I can't see this problem related to the TB as it's pretty much mechanical minus the TP sensor. Educate me if I am missing something. If the throttle position sensor was bad I would expect a different problem all together. Is there a sensor for the trans selector that can be replaced? In my teens I had an older S-10 blazer and when the torque converter whet out I was having a similar problem. The difference is that there was a lot of shudder in that vehicle while driving and decelerating. IN this there is none except when you slow to a complete stop. There will be some shudder, the revs drop, but she doesn't die. If I pull into a space and put her in park, then try to go back to drive, she dies immediately. Say you are at the drive through and you are just rolling through very slowly, foot on the brake, there is a definite shudder and it's not the rotors because they are brand spankin' new, front and back!
I still think it's something in the tranny.

 

Thanks guys. I had that TB cleaned not more than 30,000 miles ago but I may pull it again tonight just for grins. Bluegrass I do not feel like the truck is pulling any harder other than normal at the 600 to 700 RPM range but I will give her a test around lunch time. The OD light on the stick has flashed in the past, but that was many many moons ago and since I have had the tranny serviced it has not flashed. In fact the switch works like a champ. I dropped the tranny pan yesterday and the fluid was fine, and the filter was in place. I topped the fluid back off and same problem. I went to the tranny shop near me and they are leaning towards the engine, a possible throttle body issue. I can't see this problem related to the TB as it's pretty much mechanical minus the TP sensor. Educate me if I am missing something. If the throttle position sensor was bad I would expect a different problem all together. Is there a sensor for the trans selector that can be replaced? In my teens I had an older S-10 blazer and when the torque converter whet out I was having a similar problem. The difference is that there was a lot of shudder in that vehicle while driving and decelerating. In the truck there is no shudder except when you slow to a complete stop. There will be some shudder, the revs drop, but she doesn't die. If I pull into a space and put her in park, then try to go back to drive, she dies immediately. Say you are at the drive through and you are just rolling through very slowly, foot on the brake, there is a definite shudder and it's not the rotors because they are brand spankin' new, front and back!
I still think it's something in the tranny.

 

Here is the scenario:
After the truck has come up to operating temperature, it will die when shifting from Park, Reverse, or Neutral into Drive.......The motor idles as smooth as glass no matter what temp in the park, reverse, and neutral drive ranges. If I come to really hard stop while driving, the motor could die and has. At a normal driving stop the idle may drop a little but will return to the 600/700 range with a little stumble here and there. The vehicle does NOT stumble when I accelerate. In the past year and annoying lag has developed between 2500 and 3000 rpm. This occurs when accelerating at the half and 3/4 throttle angles. There is a consistant pull, the lag and then the pulling resumes (clutches?)At WOT the 1-2 shift is a bit course and definitely takes longer the 2-3 or 3-4. Overdrive works perfectly on the highway and at all operating speeds. I believe I feel a slight shudder when rolling along at low speeds or coming to the stop. My rotors and pads are brand new and true (I have less than 10k on them) so I do not believe that shudder to be suspension (it's a year old), brake, or tire related. When slowing to turn corners the power steering pump will not whine but rather make a rubbing noise and there is intermittent vibration akin to something like a bearing rubbing that is felt in the steering wheel.

To date I have done the following:
NO CODES (CEL OFF)
NO BLINKIG OD LIGHT
Replaced all COPs one week prior to this issue. The truck sat for that week at the airport.
Replaced IAC (the old one still worked but what the hell, 161k, why not?)
Replaced the PCV
All vacuum lines and ports look good. No leaks.
Pulled and cleaned (again) the throttle body and intake
Dropped transmission pan, fluid looked pretty good. There looked to be some superfine particulate matter in the fluid but nothing out of the ordinary. I had the tranny flushed and serviced with a new filter about 35,000 miles ago.
I closed the pan and topped her off with fresh fluid.

I keep thinking it is the transmission........Can some one explain to me or brief me on the workings of the transmission? I am wondering if the accumulator spring may be bad or broken? Can I replace the clutches?

I am posting this into 2 forums BTW. Sorry guys. I will monitor this from the transmission forum unless someone here is familiar with this as an engine related problem.

 

Looks like you pretty throughly went over a lot of things now.
Here is how the idle control is supposed to work.
In PCM program, the idle value is stored as a control reference.
The Crank position sensor rpm is the source the PCM uses to match against the reference value.
If there is a mismatch by about 50 rpm, the PCM opens or closes the IAC to adjust air for idle control changes. This is subject to alteration of the reference value by some other sources such as cold start signal from the ECT and other fault functions that have the ability to modify it on a temporary basis.
What you need to find out now is if the IAC is being controlled by the PCM.
Perhaps the wire harness, plug or even the circuit at he PCM is open or shorted.
This fault usually can set a code but you appear to have a unique fault that is not reportable by code.
Another way is to have a good Ford dealer tech use his test equipment to look at some of these functions and find out why the idle air is not being controlled.
Find this out and your drivability problem is solved.
Good luck.

 

I am going to take her to Ford today and see what the deal is. I am at my wits end here. To top it off, the lean codes came back last night! 0171 and 0174.
And I am bone stock with no leaks!!!!!!!!!
I am hoping the ford guys can get her right for me. I haven't taken her to the dealership before for any major service other than replacing a COP the first time it went bad. I think I was charged close to $400 for the COP and replacement of 2 boots........

If only I had a lift and a shop scan tool...............
Ill get back to yall.

 

Curious to know what was found???