Audi 80 Not idling when warm, and bad economy

Noticed that my Audi 80 1.8 is not idling when warm, and my fuel economy is shot, almost down by 90miles per full tank. I'm told it could be a cold
start valve detector located in the intake elbow, and simply needs replacing, any suggestions?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload 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.