Neil Bedwin - Hot D in the Middle East
bedwinn@om.ibm.com
All points to a Crank Position Sensor (assuming the D has one). When the cps goes there is no pulse to the pcm to set the spark timing.
Normally the problem starts as intermittant and gets worse, especially in the wet.
Check the connections and look for frayed wire where the wire enters the sensor. The cps gets it's pulses from the crank shaft so look for the sensor somewhere near the crank pulley.