98 jeep grand cherokee issues

my boss has a 98 jeep grand cherokee. V8 4x4 auto. It has a new trans, new trans case, new plugs, wires, and replaced the computer twice. It will turn over and start acts like its going to try and run then it dies off immediately. some people have told me its the crank senser. Any ideas? Im totally clueless at this point. Any info would be greatly appreciated. You can email Matthew Ward @ mward4605@yahoo.com Thank you.