Mine did that...
My old '95 Bonnie rusted out the front frame rails that the A (sub) frame bolts into. I was stopped at a light, and when I hit the gas when it turned green, the engine almost hit the pavement. I limped her home, cut up some patches, did a little welding, bought some new mounts, and put it all back together again. This was mid-December, mind you- I only had access to a stick welder at the time, so it'* not the prettiest thing. Once it gets warmer, I got a friend w/ a MIG- I'll be welding it up all pretty, and then I have a patch to put in on the rail under the trunk. Drivers side of this car is nasty, it'* a WNY car- I think Buffalo rust competes with the best of them!
Oh well, patch has about 2k miles on it, still holding strong, I'll just keep putting her back together until there'* nothing left to weld to!