Delica Canada | Mitsubishi Van Club

Under acceleration my 94 L400 has started to make a loud hissing noise, stops if i let off the accelerator. Seems like the turbo is not working/losing pressure? could this be a possibility? anyone have any advice?
Thanks!

I have reposted this under general, but i don't know how to remove it from here, hoping to maybe get a bit more feedback there.
Thanks for your info Mr. Fibble !

Hissing noise sounds like the blow off valve is having an issue - if it broke and let all the pressure out all the time you would hear a hissing noise, and lose all your power.