If you are unable to crank the engine, it should be from a weak battery. But if it happens only while driving, it should be caused by charging rather than the battery.
I would suggest a charging test to find out if the alternator is providing sufficient charge. Most parts store provides the test.
Another cause could be due to bad ground cable connections. Check if the cable that is attached to the transmission is frayed off or not securely tightened.
A faulty ignition switch cannot be discounted. There was a reacall on the ignition switch so you can check with your local dealer for more details.
Wednesday, April 1st, 2009 AT 1:44 PM