Duty cycle readings

[CTDiesel at aol.com]

Hi all....some of you may remember me from a while back and now i'm back up 
and running here.....

Has anyone come across some good reasons as to why an ISV duty cycle reading 
is at 60% when Bentley says it should be 28%.  I've check for vacuum leaks and 
there are none, also checked the a/c switch and have replaced the ISV with a 
known working one....what could it be?

Glad to be back,
DJ