Ok this will be the second thread and almost three years fighting this problem i have. Truck in my sig has on occasion a start up idle drop that when it does happen will drop below 650rpm and stall out! Ive installed new OEM Ford fuel pressure regulator, IAC valve, throttle position sensor, cleaned throttle body and mass air once a month with the proper cleaner spay, new spark plugs, new COP boots, i had the mass air checked twice one at Ford dealer and the second at a private shop, ive done countless fuel pressure readings and vacuum checks ALL with no luck fixing the problem. Fast forward to last week i made a kturn on a street and the truck stalled TWICE while turning and back up trying to make the turn...... then yesterday i was grocery shopping went to back out turned hard left then put in D and pulled right in one motion and the truck stalled while doing so.......
SO
could my power steering pump be going and causing strain on the motor making it stall or do i have to keep looking for the REAL PROBLEM?

 

I went through something very similar on my 06'. The solution ended up being replacement of the catalytic converters and cleaning the TBI very well by hand. When Ford checked the pressure drop across the converters it was pretty high - this is a common issue from what the mechanic told me.

 

I had that happen on my 2002 7.3 and it was the throttle body; I'd try replacing that as well, not that spendy for the whole pedal assembly.

 

If it was the PS pump you should be able to duplicate the issue without moving.

 

its not the cat, i had no cat for the past four years and i just recently installed a new magnaflow stock replacement cat

 

ive cleaned the throttle body about ten times and i removed it ever time to clean it also. I haven't changed the throttle body but im sure a new one is well over $300 dollars

 

and redford yes i can put the truck in park on the street and with my foot off the brake turn the wheel back and forth and its very hard to turn and when i turn off center the rpm drops but the truck jumps it back up and then when i turn the other way it drops again but the truck catches itself, so far it only stalls when i try to turn and go from R to D because i did it yesterday just to see and of course it stalled out....

 

and another problem i kinda got bogged down in a muddy field Sunday afternoon upland hunting and was rocking the truck back and forth (very easily though) and it stalled twice while doing this..... seemed to do it evertime i went to shift from R and go back into D it would drop below 650RPM and just stall

 

no one has nothing else to add....

 

well haven't had any suggestions so yesterday i can a can of starter fluid started the truck and started spraying..... no effect on truck. Did a fuel pressure test again with all normal readings. SO i shut the truck off and later on that night i went to the grocery store for a second go and start the truck, the tach fell below 500 and it stalled out plugged in my SCT and there was no codes or anything so im still searching for answers or suggestions

 

I got nothing Bud, you have done everything I would have and it still didn't fix it...

 

Only thing i can think of is the PCM! Maybe its shorted out and having an issue when i first start the truck? I will say ever time i plug in a scan tool or my SCT to check stuff i always have a P1000 code, a P1000 is a system learn code and it says i have to drive further for it to go away problem is its never goes away.....

 

I had an 04 crown Vic that did the same thing. I could never figure it out, it drove me crazy! I took it by Ford finally and they told me the PCM developed an intermittent short internally. I spent the 750.00 after having a few other minor things done and it all my issues seemed to go away!

 

I think that on 8500 pound and up that code is always present because you are OBD1..

 

ah ok thanks bigpipes, i find it funny how not either mechanic or my buddy who works at the local Ford dealer said what you did. They all told me keep driving it and it will go away..........