[Angoose]

My 2011 wrx hatch has started to make a sound when on throttle around 3,500-4,000 rpm. it sounds like a blow off valve but only happens when I'm on throttle and actually driving, not stationary. It lasts for longer than a typical blow off valve though. My car is stock besides a cat back exhaust. It seems to go away when the engine is hot enough (after about 15 min of driving) which leads me to believe its a loose hose that expands and seals properly when the engine is hot enough. But I cannot see anything specific that looks loose or misplaces. the car seems to be performing as usual but i have been hesitant to push the car much. any ideas? thanks for any help!

 

[a5m]

Most likely the TMIC to Throttle Body hose. It's not easy to inspect both ends, especially at the TB. Maybe that's why you haven't found anything. Good chance it needs replacing. The stock design makes no sense to me and is bound to leak. Mine looked pretty bad.

All the best