My well maintained 02 honda civic ex with a d17a2 is making a hissing sound only when accelerating

i have a 02 civic ex with a d17a2 in it, car well my grammas she lived in a
seniors home and walked everywhere in town used it maybe once a month,
was taken for full maintenance twice a year, i started driving it and might not
of notice it at first put when i press the gas it makes a slightly hissing noise
like a manifold gasket gone, it stops when i take off the gas, it does not
struggle in power i can hit 7000rpm no problem and pick up good. fluids all
good, its auto and sounds like its coming from the left, not the cv or any of
that and it does not get louder or quiter stays the same but only under power