Had to remove the Induction Module to replace the IAC valve this weekend. Got everything buttoned up and took it for a ride and it ran flawlessly. However, when cruising and I open the throttle all the way I keep hearing a zzzzzzzzz sound. If I'm going slow I don't hear it. It only happens when I kick it at cruising speed. Not sure if it air in the line or what but after 50 miles you would think it would of stopped.

 

sounds like an air leak somewhere. Go back over what you did and look things over. Can you hear it, in the driveway, at an elevated idle?

Got get some spray ether for diesel trucks to start with... starting fluid...

Spay this around the TB carefully... NOT the pipes, etc. HAHA!

If there is a slight leak, the engine will pick up a few rpms when the fluid hits the leak. DId you change the AC at the same time?

 

I would of thought if it had an air leak it wouldn't of run as good as it did today. Not to say that it doesn't. Not sure what you mean by AC unless it's air cleaner and if that's the case it is the same K&N I always use. I'm leaning the way of an air leak because I can't think of what else it could be. Was just wondering if anyone else had heard the same noise.