Forgot to add that the truck sat for 22 years and the owner just started driving it in the last couple of weeks. The plugs,wires and fuel pump were replaced. There was a bit of a stumble off idle but besides that the truck ran fine. No problems cruising 65-70 mph for most of the way. The first 100 miles on Saturday was warm and sunny. Sunday was rainy and colder the farther north we drove, hence the icing thought. Tried some Seafoam to clear any dirt or sticking parts but did not help.