Cold start stalling

[jaloi]

I have a 2.9 that acted up when cold weather came on.When I start it there's no high idle like there normally is.I have to hold slightly open throttle for a few seconds or it stalls.Once it's warm it's fine,I've replaced the intake air sensor in the manifold and the coolant temperature sensor with no change.I also tested the IAC valve with a 9 volt battery and it moves the actuator like it should.I did notice there is no change in the idle at all if I disconnect the IAC valve while it's running.There's no rough idle or other symptoms,in fact,it runs great once it warms up,even getting over 20mpg and plenty of power(well,for a 2.9,lol) Is it possible the IAC valve is bad even though it opens and closes with a 9v test? Kind of stumped.Thanks for any input on this!

 

[freedom5]

Check the fuel pressure at the Schrader on the fuel rail. It should be 35 - 45 PSI. I had similar problems for several months plus a slight hesitation when accelerating. Finally it failed to start. Problem was corrosion in fuel pump relay dropping voltage to fuel pump.