In rereading the info - you never stated that you replaced the plug wires. As jnovack stated, jumping sparks can do this. PLEASE BE CAREFULL, LOTS OF MOVING PARTS! Take a spray bottle with water. Start the engine. Spray a mist (don't soak) a mist over the plug wires to include where they connect to the plugs. If the engine sputters, the spark is jumping.
Also, PLEASE BE CAREFULL, LOTS OF MOVING PARTS AND NOW ITS DARK TOO! at night, no lights, the darker the better, crank the engine. Look at the engine really close with no lights. Sometimes you can see the spark jumping. As jnovack stated, sometimes you need the OEM wires. Also, this car calls for plug type, Motorcraft AWSF-32P. Sometimes not going with the OEM plug isn't good either. Make sure the gap is correct. Are you sure when you put the plugs in they are at the proper torque and the ceramic insulator didn't get cracked?
Last - not throwing a code can be aggravating. Makes it harder to figure out obviously. Keep this in the back of your mind as a thought. Could be the EGR valve, solenoid etc. I have attached a site for you to review and do this test.
Let us know.....good luck
Thursday, October 16th, 2008 AT 4:18 PM