On my 2000 Windstar, with 110k miles, I occasionally get a check engine light. The codes are P0171 and P0174(right bank too lean,left bank too lean). I reset the codes and tightened the plenum(which is the only thing common to both banks). About a month later it does it again. This started around the start of winter, and I noticed that it seems to reoccur when the weather turns cold. The last time I added a can of fuel injector cleaner(which would be common to both banks also). I thought that fixed it until today, then it happened again today. It runs fine and there are no other codes that ever show up. Anybody got any other ideas? Larry Bledsoe

Larry,   This is a common occurrance on this van.  There was a TSB that came out for this and it does involve the plenum (as well as a few other things).  If you search through the past messages of this group, you'll find the TSB number, or you can look through the NHTSA website.   One thing to be aware of, this TSB was revised a couple of times so if you go to get the work done, be sure you get the latest "fix" for it.  Also, I was successful in getting Ford to pay for about half of it, but inly becuase the mileage on my van was under 75,000.  Once you get over that, they will almosr never help you.  That is not to say that you shouldn't try though.  All they can do is say no.   Good luck.   Steven L. in