Hissing sound during light/medium acceleration??

[GILLO]

Hey I have a bit of a problem, I tried starting my car this morning and took a while to start, once it did i ran pretty rough for a couple of seconds, since then when I put my foot to the accelerator there is a hissing type sound that sounds like its coming from the back of the engine/top of dash. Its making the sound on both gas and petrol.

There is a bit hesitation when taking off from stationary and power loss on the low end, any ideas?

[drift-it]

all answers are here my friend

my commodore hisses when i accelerate

[GILLO]

all answers are here my friend

my commodore hisses when i accelerate

Thanks heaps mate missed that completly, will have a look for the purge hose tomorrow, cheers