IGNITION PROBLEM Ford Escort 98

I've been having trouble starting up my car, it is a Ford Escort 1998. The Starter is working in perfect condition, my battery is in strong hold, my fuel Pump is brand new, my alternator is new and so is the pulley, checked the ignition coil and that's in working conditions and so is the ignition module sensor. When I crank the key the starter begins to work and move the motor & the alternator and gasoline is being pushed in threw the fuel lines but no spark seems to be occurring. At times it does turn on but I have to crank the car for a good whole 30 SECONDS. Then the car begins to strengthen up until it finally ignited the engine. Most of the times it's not starting up though. What could this problem be?