02 sport trac lean problem

[DSowell88]

02 sport trac.
Truck will start and idle fine, a little rough but no hiccups. If I hit the gas it will stall, but if i feather it past 2k it runs fine. Also only happens in gear. I recently installed a new tps also cleaned the iac and maf.

Throws both bank lean codes and will miss and backfire thru the intake up to 2k. After 2k itll run alright.

 

[Trac Toy]

Vacuum leak?

 

[DSowell88]

Update:
Cant feather to a normal driving situation. Its now un-drivable but doesn't stall.

Plugs and wires have been changed, upper and lower intake gaskets have been replaced. Coil pack also replaced. Ended up changing the maf because it was faulty. It pulls a good vacuum and can only check fuel pressure by eye because the pin on the rail is jacked up. Ive also removed the cats and it did not change how it ran. Voltage for O2s read normal. EGR is fine.

After replacing the maf it ran alright for a few minutes, same when fuel filter was torn out and replaced. It will run better randomly while driving but only for a minute. Most of the time runs and idles like complete trash. Misfires, surges, sputters while accelerating and no power. Ive tried all the "common & easy" fixes no luck so far. Seemly runs better at cooler temps and gets worse as it reaches operating temps.

Down to the last thread of patience. Im hoping that someone can give some insight before it ends up in a junkyard. All suggestions are appreciated.

 

[swshawaii]

PCV elbow?

P0171 & P0174 4.0L SOHC's Sport/Sport Trac

 

[DSowell88]

PCV elbow?

P0171 & P0174 4.0L SOHC's Sport/Sport Trac

No cracks but its weakened over time. The vaccum causes it to collapse on itself slightly. Also put hose clamps on the ends just to make sure it wasn't leaking previously.
Video

 

[410Fortune]

PO171 and PO174 are USUALLY leaky intake plenum O rings

 

[R-code]

Have a shop run a vacuum leak test, they're fairly simple to do and it'll help you locate the problem.

 

[DSowell88]

PO171 and PO174 are USUALLY leaky intake plenum O rings

I have already replaced both intake gaskets.

Have a shop run a vacuum leak test, they're fairly simple to do and it'll help you locate the problem.

I live in bfe and have to do stuff at home. Tested with brake cleaner by following hoses and checking common leaks spots like pcv elbow, lines and intake gaskets. No leak to be found. Seemingly pulls a good vacuum.

 

[410Fortune]

"can only check fuel pressure by eye because the pin on the rail is jacked up. "


You need to repair the shrader (sp?) valve and check fuel psi
They sell a kit to fix fuel rail Shrader valves
Lean condition and lean codes =computer has been trying to dump fuel to compensate for the lean condition in both banks and is un able to.... likely a weak fuel pump or faulty pressure regulator

Must be a job 1 ST as in 02 they had no more shrader valve

 

[Trac Toy]

Do you have an OBD2 scanner that will read live fuel trims while running? Classic readings for a vacuum leak would show high positive (lean) fuel trims when idling that drop lower the higher you rev. Understanding short and long term fuel trims can be very helpful in diagnosing many issues. Doesn't sound like vacuum leak to me. What about DPFE sensor and/or hoses damaged or clogged?