This 2003 Ford Windstar came in with the service engine soon light on. Checking code revealed codes P0171 and P0174, banks 1 and 2 lean. I checked for vacuum leaks and none were found so I moved on to the Mass Air Flow sensor. It is common for them to get dirty and cause these fault codes. The MAF sensor is located inside the air filter housing so it had to be removed. I loosened both hose clamps and pulled the rubber boot from the throttle body and then from the air filter housing. Then I unlocked the spring clamp that holds the two halves together.
The crankcase ventilation tube also had to be removed from the rubber hose and more importantly it has to be put back in place during assembly. You can see it just to the left of the master cylinder.
After unhooking the wiring harness connector I took the housing to the bench for dis assembly. There are several locks that have to be released. I used a common screwdriver blade to pry them inward while pushing the sensor out from the other end.
There is also another wiring subharness that has to be removed. It is kind of a pain but I take my time so as to not cause any damage. Once the two halves were separated I removed the sensor from the housing using and tamper resistant torx bit socket.
This is were the actual sensor elements are located and in most cases you will find a build up or film on the element. I use a pick as shown or a small screw driver and very lightly rub the film off. Sometimes if it is heavy it will lift off in one try but most of the time it takes a little while of very light rubbing to remove the film. Some people use cleaners but I prefer to manually rub it off so as not to cause and damage to the sensitive parts. Many cleaners will damage the plastics.
Just several different pictures of the same sensor. There are two elements inside and the most problematic one is the one further inside that you cannot see.
This is just one of the possible causes. There are many and one of my readers left a link to a repair site that has more answers on this problem.
Ford has a TSB out on this for 1999 to 2003 Windstar. if you want to do it yourself, you need to go to your local parts store or dealership and ask for a “Valve cover repair kit”. This site link gives step by step instructions for the fix.
Great thread. I’m unfortunately on my second wind star with this same issue. I will try the above suggested advice and work from there. Great site, and thanks again.
A dirty MAF will cause both banks to be lean as you were thinking. The dissimilar materials and varying torques cause slight air gaps at different temperature ranges. They can be affected by vibration as well.
Mine is a 2003 Windstar with a V6, 3.8L engine. A couple of months ago, the engine faltered at idle and shortly after I noticed the check engine light was on. Mechanic cleared the code (P0171) and suggested we wait to see if it resets. It faltered about 3 months later. The mechanic said that the problem was a leak in the intake manifold and that, because of its location, the cost would be between $600 and $800. However, he said that the problem was not severe and suggested waiting again.
My question is: If it is a leak in the intake manifold, why would it be only intermittent as opposed to a continuing problem?
I understand that it is also possible that the sensor in the air cleaner tube might be dirty or defective. If that were the case, shouldn’t the problem be associated with both banks and shouldn’t I see both P0171 and P0174?
I feel your pain but I am curious, are you chasing the P0171 and P0174 codes or a stall condition? Maybe both?
Great information here , there really should have been a recall on the windstar minivan ..
Even after all is said and done , MAF cleaning , IACU replacement , new gaskets and updated isolators and still this can happen !!! Its not right and it sure has my family in a -5 star safety hazzard !!!!