97 F150,4.2V6,85K miles.Ive been using 10W30 Chevron Supreme with Motorcraft filters since I bought the truck used with 64K miles.Manual calls for 5W30,and alot of people tell me I need to run 5W30,but alot also say being I live in Florida I should stick with 10W30.Any comments,advice,suggestions,opinions are greatly appreciated.