Why does my 1996 Grand Cherokee start running rough and now it wont turn over?
Try replacing the camshaft sensor. Sounds exactly like the problem I experienced.
I don't know about a Grand Cherokee, but in a 2005 Jeep Wrangler you turn your ignition 3 times with out turning the motor over. Turn your key to start, then off, then start, then off, then start and leave in start position, a code will be displayed in the odometer area. Maybe its the same for a Grand Cherokee. If that doesn't work a scan tool is required.