1993 Ford Aerostar Engine will not start

Engine problem
1993 Ford Aerostar V6 Two Wheel Drive Automatic 94,750 miles

My 1993 Aerostar Van with 3.0 engine stopped running while going down the road. It had a little steam coming from under the hood but temp gauge showed it was not hot. Had it towed and have been trying to get it started. I have replaced the timing chain, the ignition module, the computer and the fuel pump. Engine cranks but still won 't start. I need help to find the problem. I know it has been a while since I orginally asked this question, but I have some more information. In addition to all I have listed above I have replaced the distributer. I have good blue spark, I have checked fuel pressure it is within specks. The pl, ugs are getting damp with fuel and it is firing but still won't start. Could it possible be the catalytic convertor stopped up?