Error message from Auto Zone..HELP!!

A few months ago my check engine light came on and I took it to Auto Zone and they ran the codes and said it was an oxygen sensor. I have replaced that and now the light came back on. Now they are saying no codes are coming up but now it's saying it's running lean on bank 1 and bank 2. And when I am sitting at a long stop light it starts shaking a little forward and backward and the lights flicker and it acts like it wants to die but it only lasts 1 minute or less and then is back to normal and doesn't always do it. What could be wrong??

Thanks!!
Laurie

Saying that it has no codes, but is running lean on banks 1 and 2 does not make sense. They are telling you 2 opposite things.
They would get codes, or not get codes.
Lean on bank1 is a code P0171
and lean on bank 2 is another code P0174

The oxygen sensors are often replaced on the advise of auto part store clerks with code readers in their hand. They really don't fail that often.

The most likely cause of the failure that you describe is a vaccum leak.
I could make this message long.....but I would suggest that you do a search in this forum on "vaccum"

If your windstar is 1998 or or older, I would check the PCV vaccum line that goes from the top of the upper intake manifold.....next to the trottle body......and follow it back to the PCV valve. Make sure that it is intact....and snug on the PCV valve. The elbow in the line that is right on top of the upper intake manifold can develop a crack on the inside of the elbow. Also look for any vaccum line that might have been bumped loose.

If your windstar is 1999 or newer.... visit this link for really great information on a TSB that ONLY applies to 1999 and newer windstars http://www.trademotion.com/partlocator/index.cfm?siteid=214072

If you go back to Autozone to have the codes read.....get the actual numeric code from them. They usually don't give it to you unless you ask....as it means nothing unless one looks it up in a list of OBDII codes.
You can post back here with the code....and also do a search in this forum on the code and you will find out what likely causes of that failure will be on a windstar around your year.

Ok, so I took it back in and the codes came up P0171 and P0174 which I found out could mean quite a few different things and not wanting to spend a bunch of money guessing I took it into Pep Boys and they said it was a Lower intake gasket that was causing a vacuum leak. Does that sound like a possibility? They of course charge like $550.00 just to fix that but I was curious what they would find. So I told them I would pick the van up and take care of it myself. If that is what the problem is, wouldn't that be covered under the Ford Limited Powertrain Warranty since it's part of the engine?? I still am under that warranty. If so, I think I will just take it to the dealership to have them do it for $100 deductible. Thanks for your help and insight!!

Laurie

Ok, so I took it back in and the codes came up P0171 and P0174 which I found out could mean quite a few different things and not wanting to spend a bunch of money guessing I took it into Pep Boys and they said it was a Lower intake gasket that was causing a vacuum leak. Does that sound like a possibility? They of course charge like $550.00 just to fix that but I was curious what they would find. So I told them I would pick the van up and take care of it myself. If that is what the problem is, wouldn't that be covered under the Ford Limited Powertrain Warranty since it's part of the engine?? I still am under that warranty. If so, I think I will just take it to the dealership to have them do it for $100 deductible. Thanks for your help and insight!!

Laurie

If you hear a gas knock, then it is the lower intake gasket. If not then the EGR ports are clogged. Or could be both. You can have the dealer do it or do it yourself for around the same price ($100). I do 99% of the work on all my cars. It took me about 3 hours to clean the ports and I took my time, now that I've done it once, it'll take half the time. There are a few parts to change, but you can get away without changing them, but that will only temporarily fix the problem.