Intake Manifold disagreement 2000 windstar 3.8

[murphmom]

I had an O2 sensor replaced in Dec, along with the spark plugs. Van kept misfiring so I took it back. They did a smoke test and found multiple vacuum leaks. Included was the Intake Manifold and runner control. Ford changed the gaskets on the manifold and sent me on my way. Brought the van back to them 2 days later, problem still there and getting worse. They looked it over and said the previous mechanic put in the wrong O2 sensor and spark plugs were now bad. Took van back to mechanic who gave it another going over. He printed out the O2 sensor Ford suggested and a copy of the one he put in. They are the same. He showed me a 'playback event' that shows the problem is too much air. He said that the runner control was leaking TOO much and the computer couldn't compensate for it.
I've taken all the paperwork back to Ford and asked them to contact the service mngr and the shop I used. I really don't know who to believe.

[12Ounce]

I'm sorry you are getting the "run around". Its too bad we can't just drive a car without having to be a expert of some sort .... but the world seems to be getting that way... more technical for all of us.

Was all of your service done at a Ford dealership? One, or more, dealerships? Do you have a "check engine light"? ... if so, have you had the codes read at AutoZone or some similar aftermarket parts store?

There are more places for the engine to get excess air ... the intake runner control would not be a candidate on my list of suspects.

[wiswind]

Here is a link that is very valuable for your year of windstar.
http://leckemby.net/windstar/windstar01.html

As mentioned, the bushings on the bolts (Isolator bolts) used to hold the upper part of the intake to the lower part break down due to oil.
This prevents the bolts from being able to properly secure the upper intake manifold to the lower intake manifold......and you get vaccum leaks (too much air).
I would strongly recommend that the issues mentioned in this post be taken care of.

After that, I DO remember reading about issues with the lower intake manifold leaking air where the IMRC shaft passes through.......excessive wear can happen at that point.
The solution is to replace the whole lower intake (the alluminum part).
I would only worry about this AFTER you have the improved "isolator" bolts that I mention above, as this is not real common.
If your mechanic suspects this, they can use some grease.....applied right where the IMRC shaft enters the lower intake manifold....to temporarily seal that spot to see if it corrects the problem.
If the grease corrects the vaccum leak at that spot, then they can replace the lower intake manifold.
If not, then that saves you the expense of all that labor for nothing.

It is unfortunate that the dealership seems to have thrown parts at it without solving the root cause.
The isolator bolt issue is pretty well known, and....as mentioned in the link, FORD issued a TSB on it.

Also double check the big flex hose between the throttle body and the air filter for anything disconnected or loose.
Check the hose that goes from the PCV valve to the intake as well as it could be going bad after 11 years of oil.

The correct spark plug is a double platinum, with platinum on the center electrode and the ground tab.
The brands that are recommended are Motorcraft or Autolite.
These plugs are rated for 100K miles.
Unless the wrong spark plug was used......like one of those multi-pronged fancy types.....they should still be good.

It is unlikely that the oxygen sensor is a problem......too much air gives you a lean mixture, and the oxygen sensor will report that.

[olopezm]

Originally Posted by 12Ounce

Do you have a "check engine light"?

There are more places for the engine to get excess air ... the intake runner control would not be a candidate on my list of suspects.

The CEL is a good place to start, if it is on have it scanned at any autoparts store to get an idea of what's going on.

I agree with the IMRC, it works during acceleration or deceleration and should that be the problem the van would more than likely be running rough not misfiring.

Is there any chance that the guy who did the spark plugs damaged the wires or maybe didn't seat them properly?

Best regards,

Oscar.

[murphmom]

Thank you for the responses! I had work done at a Firestone and then Ford. The check engine light alternates between flashing and staying solid. The most recent codes were P0171 and P0303.

[olopezm]

If the light is intermittent I would lean more to a problem with the wires, they might be arching somewhere. It happened before in my Pontiac...

Grab a spray bottle and fill it with water
With the engine running spray water close to the wires and along the entire length.
In case they are arching you'll see/hear sparks in the engine compartment. Works best if you do it at night.

If there are no sparks that doesn't means your wires are good. Ensure all of them are properly seated first.

It will be harder but you can take each wire off and test it for resistance, you should have about 7k Ohms per foot of wire.

Best regards,

Oscar.