I have a 03 GT 3.8 non supercharged. Was very sluggish on the highway. Really between 45 and 60. Bogging down when trying to speed up. Knew I had intake leaks and figured it needed plugs and wires. Did lower intake gasket, replaced upper manifold, put in ac deco wires and iridium plugs. MAP was broken so I replaced that too. Now the car bogs down all the time. When you rev it up slow it sounds perfect. When you rev it fast it sounds like its drowning. Oh yea I also cleaned the throttle body. Any help would be great.
