1997 Windstar rough running wet

Have the tune up checked, (wires) check coil pack for arching when wet, take a spray bottle w/water and moisten ignition parts and start van looking for any electrical arches.

Thank you - this symptom also coincides with transmission issues. Sometimes the tranmission overdrive light flashes and van starts out in 2nd or 3rd gear from a stop. This does not happen every time the engine runs rough, but occasionally they happen at the same time. Could it be a wet connector somewhere? Something that affects both? Thank you.

Now knowing the rest of the story, could be a harness or sensor connector issue, but I would get the vehicle scanned for trans codes/engine codes and start my diagnoses there.