Mystery Stalling Issue Solved ?

This issue I've been dealing with for over 5+ years with our 2001 Sport trac. No engine light or codes to trace problem. It all began years ago with a miss diagnose of a failing fuel pump by reputable mechanic (I thought). Unfortunately this stalling problem arose again the next summer months only hot weather driving. Of course the pump was now out of warranty (one year) of course I thought the pump has failed again? So contacted a friend with a lift and replaced with another pump myself this time saving $450. That's when I became educated about the "non-return fuel system" with "variable speed fuel pump" my particular sport trac inherited at birth. We have owned this vehicle from new so we are just a little bit sentimental. With only 35,800 on the odometer as of this post is the reason we kept up the trial and error of this grocery getter over the years. Anyway just a small list of replacement parts over the past 5 years: Vacuum lines and elbows, EGR, valve body position sensor, battery, alternator, crank position sensor, coil pack, wires, plugs, wrapped fuel lines near engine (vapor lock?), fuel filter, Idle control valve, PCM/ECM Engine computer, fuel pump etc, etc, etc.

Again I was thinking I finally got this fixed then the mysterious symptoms would reveal themselves during summer months, which if you drive it approx. 30 minutes or more and parked in an open parking lot in the heat and return its restarts fine but as I begin driving it would stall turning the steering wheel slightly left then it would get so bad it would stall again and again going straight as well. If you're able to slip into neutral while rolling or stopped at side of the road it would restart right away. Again no engine light, no signs of over heating. Pressing on the accelerator only made it stall worse and don't restart at all. I began to focus at the intake gaskets thinking maybe, however the idle was fine at other times when it wasn't acting up so was unsure about the gaskets.

As I mention this 2001 has the "non-return fuel variable speed pump system". So I began to again educate myself about this unique system and the different components which make up this system and what was the purpose why Ford used this. Seems fuel vapors were a concern building up in the tank. So Ford installed a recycling system (not uncommon in other makers) so the vapors that upon increase (I guess?.. maybe the heat?) the system would engage and the vacuum from engine would draw vapors (from tank) back into the engine via use of various sensors upon signals. I'm no expert but I was thinking I came upon something which turned out the be the fault of my own bad habit. The habit was over filling my tank for years. I read online about this and its not a good idea and reasons and symptoms because of over filling your tank. In my case it resulted ( I believe) in causing the charcoal canisters and sensors connected with this recycling system to fail. So my fix, I replaced both "charcoal canisters" and the "Purge Valve Solenoid" as well as the"Fuel Tank Pressure Sensor", all part of this recycling system. This system would misdiagnose in my case and causing air to enter the intake causing stalling and erratic engine behavior. Not to mention the "Fuel Tank Pressure Sensor" communicates with the PCM/ECM failing to adjusting fuel pressure as needed at the fuel rail upon engine demands. Unfortunately the charcoal canisters are discontinued and or back ordered from Ford, however I found them on eBay Ford OEM's which were from a dealership out of Texas. The replacing the fuel tank pressure sensor was a slight challenge because of location however I able using my motorcycle lift supporting the tank (3/4 full of gas) and lowered it by removing the tank strap about 6 inches to reach the sensor keeping the front bolt intact on the tank.

Well the summer is here with temps reaching well into the 100's. and today the temp showing was 114 as I drove for over an hour stop and go and turning the engine off and driving again with A/C on max. I believe the mystery is solved!!!... I hope. Believe me I have several times just wanted to drive it to the ford dealership and just trade it but always thought somewhere somehow it might be an easy fix. Unrelated, Have a friend who just bought new Maverick (sporttrac clone LOL ) and he told me his A/C stopped working and he got a recall notice from Ford the warned him not to park it in an enclosed garage because of possible of unexpected fire. He has the hybrid. I'm keeping my Sport Trac, however least to say I'm not going to be over filling my Sport Trac's tank anymore LOL

To clarify, fix was replacing EVAP Canister+PurgeSensor+PressureSensor or not overfilling FuelTank, or both?
Which 2001 SportTrac subversion is this: Job1=Early2000 or Job2=Late2000 FinalAssembly per DoorSticker?
FYI, Job1 has a "Pretzel" VariableVolume IntakeManifold,
while Job2 has a simpler StaticVolume IntakeManifold,
amongst other less obvious differences.
Thanks for your persistence & this update.

was a great story and glad you shared it, awesome ya got it fixed. and its funny how all the new gen trucks have that sport trac look.

Forgot to mention I blew out the Trans Valve Body Gasket limping home on one occasion. Found an updated rebuilt and replaced that too but really nothing to do with the engine problem that again was my own fault slamming into drive at high rev's trying to get home because engine kept stalling. Included pic of door tag for reference about production date.

thanks, good to know and good work on figuring it out..
no engine codes at any time ? interesting.

my son's WRX is having a similiar sporadic stalling/hesitation issue, no pattern to it as yet I can see. It throws a p0171 'bank 1 too lean' for which there are over a dozen possible causes.. we've vacuum tested everything and replaced a hose or two, new sensors here and there, etc etc. No luck yet. Those WRX engines are such prima donnas..

Thanks for pic of your DoorLabel; your FinalAssemblyDate is 2000Aug
Believe you've got a Job2 subversion of the 2001 SportTrac = 2000May18 or Later.
Mine is just a month newer than yours. Also looks like you've got a 4.10 Differential; 2WD\4WD?
Makes it easier for folks to answer questions if your signature includes
Year Model \ Engin \ Trans \ TCase \ Diffs \ ....

I suspect you've got a loose\corroded electrical connection that
as engine warms up wants to open up, possibly the CoilPack circuit.

Another fix I did was as suggested is a loose ground somewhere which made sense. A year or so ago cleaned surfaces and reattached ground straps off fire wall. Also rerouted alternator wire away from front of engine thinking possible electrical problem and no change. Anyway its running so far no stalling so we'll see. I included by original window sticker for information about my Sport Trac.
Thanks for input

@Vegas Sporty
Thanks for that info; per original window stickers above, you've got a
2001 SportTracJob2 \ Engin=V6~4.0L~SOHC \ Trans=5r55e \ TCase=None \ Diffs=LS4.10 \...

Hey Guys, Wanted to update my ongoing issue over the years of intermit stalling with our 2001 SportTrac. Previously what I posted reviled over the years of endless week-ends that I was looking for a needle in a hay stack because of no codes and no engine light. The biggest dilemma as with previous vehicles rolling back to the stealer-ships and or independent shop with a usual diagnostic of "can't duplicate the problem" solution. I was determined to find this needle and not give up. With the help of this website and possible issues the problem of stalling has been tested and solved!!! As mentioned in earlier posts this issue was only a warm weather problem showing up after driving and then parking and then restarting and attempting to drive off during hot summer months. My focus was steered to the evaporator boxes (two) and sensor off the evaporators (one) and the fuel tank sensor (one) located on top of gas tank. It was hot summer days over a 100 was when the stalling issues would mysteriously happen and I'd limp home starting and stopping and one time I blew the trans pressure gasket trying to get home. Anyway I'm at 100% this truck has finally been fixed!!! I mentioned to my own fault the problem presented itself over years of over filling my gas tank which ruined the evaporator system and fuel tank sensor causing the stalling issue which resulted in the fuel pump was always being miss-diagnosed which it wasn't. The fuel system is a unique non-returnable system with a variable speed fuel pump which all is orchestrated by the ECU via the sensors I replaced as well as others around engine. I have driven the truck in well over a 100 degree weather in stop and go traffic with A/C on and parking in my favorite big box hardware stores. No Problems !!!! So I'm at 100% it's fixed!!
Many thanks to you guys and this website.