P0174 code on 2002 F250 - 5.4 litre Triton

My truck is a ford f250 with the 5.4L V-8.
Autozone's troubleshooting code read that I had a "P0174".
This should mean that the Bank 2 Sensor 1 Oxy Sensor is detecting too lean of fuel mix.
Per my internet research, I changed that sensor ($55), cleaned the MAF ($10), tested the fuel pressure (35psi) & changed the MAF ($115).
I'm outta ideas & outta $$$!!!
I need this truck for work...MONDAY!!
Any body know this answer?

anybody know the answer? yeah it's none of those things! It's probably a vaccum leak from a hose at the bank of the engine or some intake seals. The worse thing is the prts you removed are of a better quality even with the mileage on them then the junk sold at the zone, I'm boggled as to why people still go there. Here's the scam, they offer the scan test for feree so that you'll buy parts from them. Most of the time parts you don't need or junk parts that are os some of the lowest quality in the industry. There's a reason they cater to the DIY'er market because the professional shops in the industry want nothing to do with most of the gargabe they sell across there counters. They're fine for fluids and brake pads, struts etc but they're electrical testing is hit or miss at best and the electrical parts they sell are hit and miss as well. You'd all be better off buying a cheap 50 dollar code reader and then going online to a site like this or a site dedicated to the vehicle you drive, research the pattern failures they all suffer and inpect that first. Not some generic chart at a parts store referenced by some kid who knows sh*t about diagnostics that's put there to sell parts first and foremost not repair vehicles.

Mr. Compton,
Thx for the feedback.
If you care to offer any further info, let me give a little more background.
Truck has 163K miles.
I've had a garage repair this engine's cylinder 2 & 3 earlier this year due to it blowing the spark plugs out of the cylinder head;
an apparent weakness in this engine...if I had known this would have bought a Chev w/ the Vortec...put 210K on my last one.
This week I had to replace the terminal on coil #3. One of the wires had come detached from the connector. Bought a replacement terminal from Ford & spliced it in. That made code P0353 clear up but now I'm fightin' with this P0174.
Truck runs but boggs down upon acceleration & just has NO power in overdrive.
In regards to your vacuum leak suggestion, I replaced the lines that run from the driver side mechanism (EGR?) to the intake mechanism then to the cruise control mech then ends up in the vacuum tank.
Where could there be a vacuum leak & how can I track it down?
Thx in advance for your help!
CR Smith

with the low power you should check the fuel system, fuel pressure ,volume and filter. If you have data you will probably see both banks lean just bank 1 has not reached the maximum threshold yet.

Yeah those Tritons spit those plugs like some oldtimers spit Skoal. Not one of Fords better ideas. The dpfe sensor which is related to the egr system that you worked on can generate that code but it often generates the po171 with it so if it's only 1 bank crossing the threshold enough to generate the code the fuel trims are probably close on the other bank but not there yet to generate a po171. I seem to remember a pcv hose or something like that at the back that would get really squishy and throw the code, as well something about intake gaskets seems to come to find on some of the Ford trucks. So it could be a vaccum leak to one side although it's probably affecting both just not equally yet. As well fuel pressure is always worth a check with lean codes of any type. check it like a conventional vaccum leak looking for an rpm fluctutaion but alot don't repsond this way any more, you only catch it with fuel trims on a scanner.
Good luck and keep us postted on your findings