1992 Isuzu-High Idle problem

Please help. Whenever I run the air conditioning on my 1992 Isuzu Rodeo XS 4x4, the engine revs way up whenever I push in the clutch. Also my Tachometer doesn't work all the time. Any suggestions for either?

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

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.