Hi all,
I am working on a friends 99 6cyl Windstar after he got both 171/174 codes. When I reach in and rev the throttle I can hear a whiff or sniff of an air leak behind the plenum. I am going to rip into it this weekend, but I am wondering what the general cause is that most of you find. I don't think any of those vac lines back there have come off but couldn't get my hand back there to tell. Then I found that great webpage dedicated to replacing the plenum lower gaskets(6 of them under the plenum) and some screws. Is this a common fix above and beyond the replacing of the valve cover gasket? Are you guys 99% sure one of those 6 lower plenum gaskets have failed (due to the bolts failing in the bottom of the plenum?) or should I assume there is a cracked vac line back there and just rip into it and locate the busted line (if it exists). I guess I should just go get the screws and gaskets and if it is a busted hose then just take them back? Did I just answer my own question?
Here is that webpage as i am sure someone will say "what webpage?" :-)
http://leckemby.net/windstar/windstar01.html