I have a whistling that is directly related to rpm under load but only occurs above 10 mph... It sounds like a belt squeal, just a little higher and at lower rpm it puffs.... like airflow.. I am looking for a diagram for the vacuum lines if anyone knows where to find one???

99 discovery II

 

check your idler pulley is it made out of plastic or metal? and if it is metal does your cruise control work?

 

metal, and yes, the cruise control is fine

 

sometimes an excessive amount of dust can build up on your pulleys and can cause a whistle type noise. if you live in a dusty place try blowing them out with an air gun. and i will get you a vacuum diagram, and the sai injection routing. check all the above and let me know if it gets any better.

 

well. dusty isn't really applicable. We are in fairbanks alaska and the problem started around -20 weather, but temp doesn't seem to matter.. it's breakup now and we have driven through deep water and soaked the entire engine compartment, to no avail.