My MkV Hisses constantly under throttle with no release sound. Also lost power. I cannot find any obvious leaks.
Originally, I was Registering the CEL for MAF and P0299 (Underboost). I've replaced the MAF sensor, relieving me of the first CEL. I was hoping a DV swap would help as stated above. Upgraded to the newer rev OEM DV, but, I'm still having the same issue. I AM glad that I replaced it though because the stock unit was completely shot!
...PS, really liked the timeliness and support of ECS, where I purchased the DV