There's a couple of possible causes to your problems.
First, check your battery cables. (At the battery and where they terminate on the frame/engine block) Make sure there's no corrosion or loose connections. If so, fix.
Next, check the alternator connections. (The red bat cable as well as the connector for the voltage regulator)
Then check the engine strap that grounds your electrical system to the frame.
You need to eliminate the basics before suspecting something major.
If these check out, I'd say your starter is either failing, or you have corroded/loose connections at the starter's solenoid.
It's also possible you have a failing ignition switch. This isn't uncommon on your vehicle and its age.
A quick test would be to turn on the radio and head lights. Then attempt to start your car normally. If the engine doesn't turn over and your headlights and radio shut off, then it's either the bat, the alternator or the cables connecting them.
If your engine doesn't turn over, but the headlights and radio stay on and strong, then it's either the starter has failed or the ignition switch is failing.
Once you narrow the issue to one particular system, then you can diagnose and repair that system from there.
Monday, January 18th, 2010 AT 6:51 PM