Rev problem 18 zetec Mondeo

I have an 2001 18 zetec Mondeo , the problem is when I put my foot on the clutch to stop , the battery light comes on as if the car is going to stall,
but doesn't. The revs seem to go right down then bounce back up to just under 1000 revs. Any ideas ?
many thanks for any info
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
could be the idle speed control valve
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.