Originally Posted by Kreyton
Hate to Necro this thread but it seemed relevant to my issues.
I have the exact same issue as OP. Going up hill hear the same sound, level off or gas off sound leaves.
One thing though, if I hit the overdrive off, the sound immediately vanishes. Any reason it would do this if it were indeed the IWE's as well?
Lower load in 3rd gear compared to OD. Which results in more engine vacuum, since vacuum is inversely proportional to load.