2003 Jeep Liberty 3.7L V6 - Start Stall When Cold

I have had this issue for over a year now and it has gotten progressively worse.  No DTCs, check engine light is off, when the engine is cold it starts and then stalls, the only way to keep it running is to press slightly on the gas pedal.  This is not a drive by wire system, it has a physical cable between the gas pedal and throttle body.  
When the engine is warm it will idle fine most of the time (~80%), but sometimes even when the engine is warm it will not idle without opening the throttle plate slightly via the gas pedal.

Items replaced:

• Idle Air Control Valve
• MAP Sensor
• Intake air temperature sensor
• Camshaft sensor CMP
• Crankshaft sensor CKP

I've uploaded some videos to show the symptoms. 




youtube.com/shorts/-j4mdSoSU2k?feature=share
 

Appreciate the videos, AnthonyB. 

Having to keep the throttle plate open when cold is a pretty solid indicator that the engine isn't getting enough air. I saw you already replaced the IAC motor, which is good. Did you clean the throttle body, as well?

I don't remember what it's called exactly, but there's a scan tool function for clearing the IAC values. Your Autel looks like it'd have that under Active Test or Special Function. Or, have you done that already?

I did clean the throttle body as well.  

Good call on clearing the IAC values, I had not done that.  It was under Special Function >> Reset Memory >> IAC Counter.  I cleared it and do notice the values are much lower now.
Before clearing the IAC counter engine cold values were 150-200 steps, engine warm ~50 steps.  Now engine warm ~20 steps.  Seems to idle fine, will find out more over the next few days when starting after it has been sitting overnight.  

Thanks for the tip!

 

No worries! Absolutely let us know how it goes.

I found a temporary fix to the idle problem.  Not sure where to go from here.


 

The next day after the soft battery disconnect, clearing the PCM memory.  Engine cold.  Unsure if IAC of 150 is too high with cold engine.  The next time the engine is cold and start/stall is present if I see ~150 for the IAC I'll perform another PCM reset and see what happens.  

I've tried to rule out inputs as a problem.

• TPS - checks ok via scan tool
• ECT - checks ok via scan tool
• Idle loads - A/C switch, Park/Neutral switch, Power steering high pressure switch
  • Not shown in the video but check good via scan tool
• Unsure about the vehicle speed sensor, I'll check to see if there is a data PID, speed gauge shows 0 MPH when stopped.  

I drove the vehicle after the video until the engine was warm and the idle was fine, IAC ~20 steps.