Strange noises

I have a 2002 mustang GT Automatic With 18000 miles on it.Yesterday,While backing out of my driveway,I heard a slight popping noise.As I drove on,I heard loud horrible clunking or grinding type noises from either under the car or one of the wheels and it felt as though I had a flat tire.The noise stopped for several seconds then came back again,this time really loud.I pulled over and checked the wheel lugs and tires and looked under the car for any leaks or anything odd.there was nothing.I restarted car and drove away and the noise was gone.Does anyone know what could be causing these noises?I was driving straight and I wasn't using my brakes at the time so I don't think it is my wheel bearings or brakes.

Welcome to AF!

Has it happened again? You mentioned that you drove off after it did it. I suspect you have a failed lower ball joint on the lower control arm. You can check it by putting a jack under the control arm and just lifting the tire off the ground. Grip the tire at a 12 oclock and 6 oclock position and try to move it up and down. If you have any play it is the lower ball joint that is bad.

If you aren't handy around cars, I might suggest you take it to a front end specialist and have it aligned. He will check the front end for wear/damage before attempting to align it.

I haven't driven it again yet.I am afraid of something happening.Thanks for your advice.I will try what you suggested.

I did what you suggested.there is no play in either wheel.So it is not the ball joints.Does anyone have any other suggestions?