'98 with PO171 and PO174

[Fordina]

Can someone tell me what modifications to make to the www.leckemby.net/windstar/windstar01.html fix for getting rid of the PO171 and PO174 codes on a '98????? I believe his site (awesome write-up on this repair) applies to '99 models and above specifically. I need to know what to expect when going into this repair on a '98. Thanks for any help!

[wiswind]

You are correct, the repair for the 99 and newer that is outlined on that site does NOT apply to the '98 and older.....as the isolator bolt seal issue happens with the newer style upper intake manifold that they used starting with the '99 model year.

However, the codes that you are getting are also most likely caused by too much air getting into the intake......because of a vaccum leak.
It could be from a cracked, loose, or disconnected vaccum line.
You could start with the flexible elbow that connects into the top of the upper intake manifold, next to the throttle body.
Mine developed a crack on the inside of that elbow.
Then follow that line back......to the PCV valve in the rear valve cover.
Make sure that the line is intact, and everything is connected to it.
It branches out into several other lines that go other places.

There are other vaccum lines that connect to the back side of the upper intake manifold.....including the fat one that goes to the power brake unit, one that goes to the IMRC actuators, and one that goes to the fuel pressure regulator (next to the IMRC actuators on the passenger side).

Also, do the heat controls work correctly?......the control of where the air goes (floor, defrost, etc) is driven by a vaccum line from the rear of the upper intake manifold also.

Another line to check is the stiff plastic line that goes from the front valve cover to the back side of the flex hose that goes from the throttle body to the MAF / Air filter unit. Make sure that it is connected at both ends....as well as the flex line being snug at both ends.

I have not read anything about the flex line between the throttle body and the air filter unit being prone to developing cracks as was the case on some vehicles in the past.....so they seem to have corrected that for the windstar.

Another possibility if it is not a vaccum leak, is a dirty MAF....
I have pictures posted that show where to spray non-residue electronic cleaner to clean out the MAF.

It is almost certainly not caused by any problem with the oxygen sensors.

[Fordina]

Wiswind, our family just wanted to say a HUGE "thank you" for your wonderful post. You have helped us out immensely this time and in times past. It wound up being a loose vaccum -- just like you said. It was able to be fixed in minutes. The clue was the defrost was out in the van, as well. You saved us from that huge www.leckemby fix which would have been disastrous in our case. Thank you, thank you!!