2005 Escape P0171 (lean code)

I wanted to do a smoke test, before throwing parts and service @ this truck.

1) Put some Glad wrap around air filter to block any air flow.
2) Removed brake booster hose.
3) Using a Black & mild cigar to blow smoke through the brake booster vacuum hose, and plug with thumb in-between puffs.
4) Watch for any smoke leaks, and focus on the PCV, EGR, and Intake systems.

The Intake is leaking, I wonder if there's a
Recall, bad gasket, bad intake, or torque spec?

I'm assuming it is a V-6. I don't know of a recall. Most likely intake gasket or PCV hose at the PCV under the intake. If someone washed the engine they got water in the sparkplug tubes and had to remove the intake to get at the back plugs (or they were doing something else for the plugs). Could have knicked or unseated a intake gasket in the process. The short rubber hoses at the top of the intake and below to connect the solid tube for the PVC are famous for drying out, cracking and starting a vacuum leak. The top one is easy and the bottom one requires taking off the intake. So I'd say your going to probably have to pull the intake to see which it is.

2005 Mazda Tribute 4-cylinder with 120K miles.
The PCV oil might of contaminated the O-seals on the intake gasket
The SUV runs good, but throws a P0171 30miles into the drive cycle.
I'am suspecting oil from the PCV system, I had to clean the throttle plate 3x during the 120k miles.

The Mazda shop wanted $115 for a smoke, mine was $1.49.

Got http://www.Alldata.com ,and some new Intake gaskets today.
Yep! Intake gasket looks bad.

Root cause was a bad rubber PCV crankcase tube behind the Intake.
$20 for Inake gaskets @ AutoZone, or $40 @ Ford
$40 for a rubber PCV tube from Ford.

One $40 Acme Auto Emissions Filter to help protect my H02 sensors, MAF/IACT sensors, throttle body, and catalytic converters from emission gunk, see http://www.ideabuyer.com/ipavail/acme-auto-emissions-filter , we actually picked up 3 more MPG (Total 26MPG) @ 70MPH on Hwy.

Root cause was a bad rubber PCV crankcase tube behind the Intake.
$20 for Inake gaskets @ AutoZone, or $40 @ Ford
$40 for a rubber PCV tube from Ford.

One $40 Acme Auto Emissions Filter to help protect my H02 sensors, MAF/IACT sensors, throttle body, and catalytic converters from emission gunk, see http://www.ideabuyer.com/ipavail/acme-auto-emissions-filter , we actually picked up 2 more MPG (Total 25MPG) @ 70MPH on Hwy.

Thanks for posting back the fix and the tips!