Hello all, '96 classic 4.0, I hear a high pitched squeal while driving, not constant just when I let off the throttle and the Rpm's drop then when I press the pedal to start going again, it only happens while at highway speeds and not from a dead stop, when I'm in the left lane I hear it do it sounds like its coming from the left side of the engine, I never hear it with the windows down coming from the r/s, it happens for about a second or so, possible vacuum problem? This has been happening for about 2 weeks and now while at a light, I can hear the belt starting to squeak, connected? Thanks for any help

 

I'd check the condition and tension on the belt first.

 

X2. Check the idler pulley too. Bearing might be on its way out.

 

Yup it's the belt lol I'm doing the head gasket and putting a new header on next week, it's on the job list, thanks for the help