A couple weeks ago my car (3.8 Litre V6 L36) would suck in air when i put some throttle down or when i went to speed up on interstate, i noticed i had a lower intake manifold gasket leaking and figured it was due to that, so i replaced the lower intake manifold gaskets, upper intake manifold gaskets, valve cover gaskets, and throttle body gasket, but the loss of power and air sucking noise still continued. I also noticed i had a plug wire that kept shorting and sparking on the engine bracket so i replaced plugs and wires last night. Took it driving today, still didnt solve the problem. Does anyone know what this could be? When i give it throttle it revs and has no power behind the rev, sounds like air is being sucked in

Thanks