2002 Sport Trac - P0171 P0174 Both banks lean ?

Hi,
My wifes 2002 Ford Explorer sport track with the 4.0l V6 is throwing codes of p0171 and P0174 which i find are banks 1 and 2 lean.  I have been all over it for vacuum leaks using propane and brake clean.  Neither seems to make a change.

It starts hard and idles poor,  sometimes alot worse than others and has even stalled at idle a few times.

I tried to put my fuel pressure gauge on the fuel rail tonight and it seems like it is not pushing the schrader in far enough to read as it reads 0 psi while running. 

LTFT bank 1 is 25
STFT bank 1 is 27.34
LTFT bank 2 is 25
STFT bank 2 is 23.44

Im not sold on it being a vacuum leak as i have checked the intake gasket areas with a combustable gas as well as the vacuum lines.  I am wondering if a fuel pump could be the cause.

Any help would be greatly appreciated as im leaving for work in a few days and would hate to leave her and the kids with an unreliable vehicle.
 

Tbh, I would use a smoke machine. It really is the best way... Propane, I find, doesn't always work.

Anyway, SD mentions a few things.

Fuel pressure
MAF
Maybe the o2s are lying? Although that's rather improbable.

Have you tried raising the rpms to see if the fuel trim gets better? 

That's used as a way to gauge if the problem is at idle or higher rpms.

And if it's both banks that means it's highly probable that something shared is the cause. 
Fuel, MAF (air), vacuum leaks.

If you use propane you have to monitor fuel trim as well. Stft will go negative if there is a leak. Sometimes, it's not enough to just hear if there is an rpm change.

Thanks for the advise. I tried again with brake clean and seemed to be getting no where watching the trim on my phone. Out of desperation I started unplugging vacuum lines one at a time and capping them with my finger while looking at the trims.

I eventually pulled a larger line heading down to the evap canister and plugged it off. the trims went slightly negitive and stayed there so far. I left the cap on. I just sent her out to pick up the kids so we will see what happens after a bit of running around.

Hope its the fix that will get her by until i get back and have time to pull the wheel tub and alot of other crap out to see where the actual leak is.

Dose anyone see an issue with running it like that for a month or so?

Thanks again for the help.

It sounds like you may have found the line that goes from the purge valve to the vent valve. It's possible that the purge is stuck open, causing your two-bank lean condition. Noah recently made a great video that can be seen in the Premium Video section here where he shows how to test the purge valve, if you are a premium member.  One way to test is to monitor fuel trims and pinch off the line going from the purge valve to the vent and see if the trims go closer to 0.  You want to do this when the purge is not purging, clicking.  This may be, essentially what you did before, but we aren't sure if it was purging at the time, or what the trims did exactly.  

Keeping that evap line pinched off will likely set a code since the ECM will think the vent is stuck closed, or restricted.   You want that vent to be clear so that the cannister doesn't get saturated with fuel.  

Keep us posted!

Your fuel trim on Bank 1 is 52.34% .Bank 2 is 48.44% .
As suggested earlier- checking your fuel trims at 2500 and 3500 rpm would point you in the direction to be taking next. You stated the fuel rail pressure was 0 psi.
That reading may not be far off the true reading.