What's wrong with my 98 Jeep?

[jordan s]

I have a 98 4cyl wrangler that I just can't seem to get started. Here is what I know of so far....Jeep spins strong, and will crank with ether. fuel system seems to be fine but the jeep fires intermittingly. I have since replaced the plugs, cap, and rotor, only to find that none of those seem to be the problem. I have been told that it could be a crank shaft sensor, but am reluctant to spend the money without knowing for sure. Any ideas are appreciated