My 99 Windstar has had many problems recently. After having my transmission re-built a year ago, it started leaking anti-freeze into the transmission coolant (no other leaking). This of course caused all kinds of damage inside the transmission and more costly repairs. Somewhere during this time, it also started giving "lean codes" (p0171 & P0172). The transmission is repaired and again gave us the lean code. We had a shop try to diagnose the source of the lean codes. We do not have a vaccume leak or exhaust leak and our oxygen sensor is working fine! As we also needed to go through emission tests for our license, after the mechanic returned our van yesterday and we ran errands both then and today, we had our emission test....passed. Late today our service engine light came on AGAIN. This will be the 3rd time with this issue

Does anyone have a suggestion as to what I can do next to resolve this issue! Thanks for any help given

 

First be REAL sure there aren't any vacuum leaks. Fords use plastic lines to route vacuum and the rubber elbows that connect the various tubes are notorious for collapsing and splitting..........Pay particular attention to the PCV line........If all is well there, be advised there IS a bulletin on Mass Air Flow sensor contamination.............but I'd be betting on a collapsed elbow

 

Thanks for the suggestion. I will check it out.

 

Is the vehicle running o.k., No spitting or sputtering, or hesitation ?

 

It seems to be working fine. 2-3 times a month (I think the weather may be a factor). In the AM when leaving for work....in the same location (stop light) it will start lurching and acting as if it wants to cut out. A little gas solves that problem. I believe it's connected, please keep in mind that I am NOT a mechanical person. I only just learned how to change my own fuel filter last year!

 

question: did you find the source of the water in trans.? sounds like a leaking trans cooler at radiator??
if it is running lean, it is getting too much air. if it is my car, i would be looking for an air leak. spraying a little wd-40 around places that can leak might tell you. if it speeds up when the spray is applied, you have a leak.(the wd-40 will dissipate shortly and won't hurt elect. comp.)

 

they do have lots of problems with those rubber elbows...but ford also programs them to run on the lean side anyway, so it doesn't take much to go wrong to push you out of the normal window and trip the light. you passed emissions because it wasn't lean enough to cause misfire yet. the crappy running at times when cold is VERY indicative of an air leak. many car makers are having troubles keeping their composite intake manifolds sealed up to the cyl heads. if they leak along the bottom, wd-40 won't find it and it will stink inside the van...best bet is to have someone smoke test it. that's a definitive test...just did one on a very elusive lean running problem Silverado 5.3 (+25% LT fuel trim on both sides with P0171 and P0174) and it was the intake gaskets. and guess what...his wifes 2000 windstar is doing the same thing...guess what i'm betting on? can't wait to smoke test that one...good luck

 

it seems I have quite a bit of poking around left to do!
Yes the source of the radiator leak, yes, it was the trans cooler at the radiator.
I will look into the smoke test and keep looking for the air leak, good idea with the WD40. Thanks to everyone for all of the wonderful suggestions.

 

Ok, so I stopped to have the codes checked because my o/c off light came up flashing over the weekend. (3 seperate times, only stops when engine is turned off). It would not come up with any codes to show what the problem is! Any suggestions!? My transmission mechanic won't look at it unless I can show that it's a transmission issue (as I suspect), but how can I do that if the code doesn't show up??

While I was looking for that information, we discovered that the Lean Codes were slightly different than the ones I listed from the previous scann....this time they are codes p0171 and p0174. Any thoughts on the different code?