TennesseeMan, yes, if you were found to be carrying a loaded weapon in your car, without a HCP, you would almost certainly face criminal charges, whether you used it or not (pulled over for a ticket, etc.). Until you get your carry permit, unload the weapon and keep the gun in one part of the car and the ammo in the trunk (and I mean the trunk - my carry class instructor was a Madison Co. Deputy and explained that without a permit the gun and amma had to be in SEPARATE compartments of the car), or carry a nice knife or pepper spray. I completely understand the feeling that you may need to carry, but carrying without a permit is a very risky proposition.
Lastrebel, you are correct about being able to carry a rifle or shotgun in a car now, but only as of 2010 I believe. So when this post thread was originally posted the info given was accurate, for the time.
Native Memphian here!