I really dont know what to do. the light keeps coming back on and I have done everything that I know to do. I just replaced the isolator bolts (even though i already had the new ones), and i replaced the vacuum tube on the front (including the rubber boots), I have replace the 6 rubber port seals, the gasket in between the upper and lower intake plenum. The only code I am getting is p0174. The next thing I am planning is taking it to ford and having the PCM re-programmed for $93.

Is there anything else I can do? Is there something I am overlooking?

Thanks

[EDIT]
I just replace the 2 big hoses on the back of the intake plenum. One connects next to the throttle body, and the other one is more in the midde on the back of the lower plenum.

Could it possibly be the DPFE? I can get a replacement from autozone for $52.00, but I already have the plastic one.

dichmagnet

You've probably have already read the sticky post at the top of the forum. I copied the P017X section for you:

This group of codes indicate a condition that the indicated oxygen sensor is reporting.
These codes are almost NEVER caused by a defective oxygen sensor or sensor circuit.

P0171 Oxygen sensor reporting too lean condition on bank 1 (rear bank)
P0172 Oxygen sensor reporting too rich condition on bank 1

P0174 Oxygen sensor reporting too lean condition on bank 2 (front bank)
P0175 Oxygen sensor reporting too rich condition on bank 2

Lean codes almost always are a result of a vaccum leak (all years and engines).
1999 3.8L and newer windstars refer to sticky post on P0171 / P0174, this TSB does NOT apply to 1998 and older or 3.0L engine.
Lean codes can also be a result of clogged fuel injector(s) or fuel delivery issue.
Rich codes can be caused by a leaking fuel injector or misfire due to no spark to one or more cylinders
Lean and rich codes can be caused by MAF issues (try cleaning)

How old are your O2s? They do fail. I know that they are blamed for many problems where they are just the messenger.

Regards

Dan

the O2s are brand new, cause i did replace them. the van is at ford right now and they are saying the gaskets (also new) are no good cause there was too much presure on them (which I dont belive) but they want do to the job for $680 cause they say it will take 5 hours. I have done the process like 6 times now and I can do the whole thing in less than an hour...I am so mad...
I want to keep it, but i think i will have to sell it unless I can figure this out.

please! does anyone have any ideas?

Any air leakage into the engine can cause codes. There are air seals all over the engine ... front cover gasket, oil pan gasket, lower intake gasket, (on and on )...

You could swap the injectors, front to back ... and see if the code changes. You could also swap the spark cable caps among the cylinder "siblings" to see if the code changes .... ??

Ford has said that the intake plenum is warped, so they are replacing it

Anything they remove, ask for it back and get them to show you the damage. It will keep them honest and you may learn something in the process. Good advice for any shop you go to.