MegaCab_PL wrote:
Not sure if the OPs v10 has the idle speed valve. My 4.6 from the same family does not IAC, all rpm control is in PCM. Clean the throttle body.
Correct.
Not ALL modular engines have IAC.
Between 2003 and 2006 on the modular engines the IAC was eliminated and the throttle body went to electronic drive by wire.
IAC AND cracked vacuum lines are chief culprit of the symptoms tho OP is experiencing for non electronic drive by wire throttle body.
For Electronic drive by wire throttle body the symptoms the OP describes is dead on with a sticky throttle body..
If OPs vehicle is 2005 or newer I would bet that the throttle body plate is gummed up. This causes the computer control to go into limp mode when it gets severe enough but until then it will stall ONLY when at a stop and shifting from drive to park or reverse to park (note that the engine RPM will often drop from 600 RPM to less than 400 RPM when stopped with this condition).
When throttle plate sticks severely enough the computer commands limp mode, turns on the WRENCH light and DISABLES all throttle pedal response.. So fix it now, before you find yourself going up a hill with a load and no throttle..
This IS a very common problem that no dealership will talk about.. They simply replace the throttle body instead of cleaning it.
In a nutshell, the PVC valve vents the oily vapors from the crankcase right below the throttle body.. Those oily vapors will build up layers of gummy sticky residue on the throttle plate and around the throat of the throttle body until the throttle plate can no longer move or return to fully closed position.
Throttle body can be cleaned without removal but you will need some help or a way to prop the gas pedal to the floor with key on..
Do a search for cleaning a modular throttle body.. You will find some step by step instructions.
