When was the last tune up (plugs, wires, rotor, cap)? The ignition components on these cars need to be replaced on a fairly frequent basis - about every 30K miles.
Could be timing belt Remove the distributor cap and while an asistant cranks the engine, see it fhe distributor turns. If it doesn't the timing belt needs to be replaced. Or remove the upper timing belt cover (I'm assuming this has a 2.2 or 2.5L engine) - even if the belt is still on, it may have slipped a tooth or the teeth have stripped off.
