# GM gurus: 2.0L S/C ECOTEC hissing under acceleration **URL:** \ **Category:** Shift518 Automotive\ **Created:** [March 8, 2012, 6:44pm UTC](https://forums.speedlife.net/t/gm-gurus-2-0l-s-c-ecotec-hissing-under-acceleration/262945 "2012-03-08T18:44:45Z")\ **Posts on this page:** 1\ **Showing post:** 8
**Author:** ![toomanycamaros](https://avatars.discourse-cdn.com/v4/letter/t/7993a0/32.png) [@toomanycamaros](https://forums.speedlife.net/u/toomanycamaros)\ **Post date:** [March 9, 2012, 7:23pm UTC](https://forums.speedlife.net/t/gm-gurus-2-0l-s-c-ecotec-hissing-under-acceleration/262945/8 "2012-03-09T19:23:39Z")
> [@new skins for the monte](https://forums.speedlife.net/t/new-skins-for-the-monte/48515/26): > > OK, if I pump the brakes while at idle, should the car lose vacuum? The idle gets rough and when I stop pumping the brakes the car sounds like it wants to die. Also, I looked and the vacuum assist for the brakes is pulled from the blower. Could this be why boost has dropped? yes there should be some minor fluctuation. The brake booster operates via manifold vaccum. Also a faulty booster could cause a leak and give you issues, however that would be rather unlikely IMO. I work at a dealer and have never had to replace a booster on a cobalt. I would look at the car with you, but I’m up in Plattsburgh. Honestly your best bet really is to PM 88slowmarro and throw him a couple bucks to look at the car for you rather then trying to have the collective minds here on shift diag it through the keyboard. Also CEL on or off? --- _[View the full topic](https://forums.speedlife.net/t/gm-gurus-2-0l-s-c-ecotec-hissing-under-acceleration/262945)._