"Check Engine Light" on, but no DTC.

It's on my 1999 Ford Windstar. I just cleared the codes (I think they are P13171 and P13174), but "Check Engine Light" won't go away as previous occassions. It runs fine.
Has any one encountered this problem?
Alex.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Do you mean p0171 and p0174 ?
Means you probably have a vacuum leak at the upper intake manifold You can get updated gaskets and bolts for that. there is also a PCM update that takes care of little leaks from the lower intake runners
good luck
Johan

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks, Johan,
You are right. DTC's are P0171 and P0174. Thanks for the hints.
Yesterday, I checked DTC's again and same codes plus P0741 showed up. This time, light was gone when I cleared the codes. Don't know why it didn't work last time.
From DTC descriptions, it seems P0741 is much more serious. Any suggestion on course of action?
Alex.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You'll probably find the answers at this site http://www.obd-codes.com

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.