I posted this over in the f250 forum thought I would post over here too(hope that's ok).
Have a 2005 f250 with ~200,000 miles on it. Have done regular maintenance on it and have all of a sudden develop a engine problem. On start up the engine will barely run. If left alone the engine will idle between 500 and 1000 and then die, absolutely no power. The truck is undriveable.
A year ago replaced phasers/timing chains/tensioners/guides/oil pump, two years ago replaced spark plugs.
Getting lean both bank codes, fuel trims are all reading zero % and pressure hovering around 40psi. Feels like a vacuum leak so I checked all the hoses even the one on back of engine. Thought I had leak at the manifold gasket area, went ahead and changed the gasket and decided to install a new intake manifold too. Problem still there.
I'm at a lost, any help would be great.
Thanks

 

what codes does the truck's computer report?

 

Only two codes 2195 and 2197. Today removed and sealed the vacuum hoses coming off the intake still no help.

 

Have you had the MAF checked/cleaned?

 

Check FUSE 33, Central Junction Box @ Right "A" Piller. It supplies the Violet/White wire coming out of the Central Junction box and sources 12V to the heater element in the Upstream O2 sensors. The PCM switches the other side of the heater elements to ground. One of the causes of your reported condition ("Oxygen Sensor Signal Biased/Stuck Lean") can be Open or Short in the heater circuit. But since your problem is the same on BOTH banks, seems the ONLY thing that is common to the 'condition' being reported.


You can trace the circuits out on the attached Wiring Diagram from top center of page 1 to the bottom right of page 5-of-6.

EDIT: Guess file too large to upload to Forum: You can download it from here: http://www.devoll.com/Public/f150-5_...nce-wiring.pdf

Hope this is what it is and easily scotches the problem for you.

 

I had some more time today to mess with the truck. Had a friend sit in the truck while I sprayed starter fluid into the intake. Truck ran great, think I have some clogged injectors. Going to take them off tomorrow and rig up an injector tester.

 

Dude replace the fuel filter.

 

Keep it simple. The truck has 200k and runs lean but runs. I'm sure it surges and falls on its face when you accelerate. Injectors are fine. I bet you've had small issue up to this point. 100% sounds like the PO for an old clogged fuel filter.

 

???
Regular maintenance includes fuel filter.

 

You never know what some people consider reg maintenance. On the backside of the throttle body I remember there being an elbow emission hose the wears a hole in it and causes that same issue.

 

If you're original post remains true...
"Getting lean both bank codes, fuel trims are all reading zero % and pressure hovering around 40psi." ... "went ahead and changed the gasket and decided to install a new intake manifold too"
... how do you justify still spraying carb cleaner when the only two codes mentioned so far are P2195 & P2197.

P2195:
- Faulty Front Heated Oxygen Sensor Bank 1
- Front Heated Oxygen Sensor Bank 1 harness is open or shorted
- Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection
- Inappropriate fuel pressure
- Faulty fuel injectors
- Intake air leaks may be faulty
- Vacuums leaks


P2197:
- Faulty Front Heated Oxygen Sensor Bank 2
- Front Heated Oxygen Sensor Bank 2 harness is open or shorted
- Front Heated Oxygen Sensor Bank 2 circuit poor electrical connection
- Inappropriate fuel pressure
- Faulty fuel injectors
- Intake air leaks may be faulty
- Vacuums leaks

You have already replaced the intake manifold & gaskets. Plus vacuum leaks will result in P0174 or P0175 and elevated fuel trims - before the DTC's reach "STUCK" lean on O2 readings -both banks. It's Unlikely multiple injectors gave up at one time. You said fuel pressure is around 40psi. Seems unlikely BOTH O2 sensors die at the same times. The only thing logically remaining in the above DTC descriptions that are common to BOTH banks is circuit related.


If it turns out to be something else, I - for one - would really like to know what you ultimately find.