Make sure you have delco suppression plug wires or equivelent, and also make sure you have the correct resistor spark plugs in the engine. saw this problem in an 05 taurus, the guys at work replaced entire wiring harness under warrenty,this did nothing. engineer came out to our dealership, and said replace spark plugs. WE gave him dumb looks, BUT IT FIXED THE PROBLEM! BELAIR MIKE