Hi all, my girlfriend has a 96 thunderbird lx 4.6 L Auto. And about last year we discovered a crack on the intake manifold, DOES NOT run into the block. It sprays coolant on the engine at high rpm's. Anyways.. About 6 months ago the car will make a loud humming sound, and I mean LOUD. You can hear it inside when she pulls up. It seems to also do it more when you turn on the heat. Also sometimes when it happens, the car will maintain its speed. Without pushing on the gas it will drive itself, almost as if cruise control switched on. Anyways, you guys are great with mustangs, They are not too different, hoping you guys can help us out with her Thunderchicken! Thanks!