You must find your engine's specifications to determine the correct gap. This information is usually found:
* On a sticker under the hood: Look for a sticker that details engine size and specifications.
* In your owner's manual: If you still have the original manual, it will specify the correct spark plug gap.
* Online using your VIN: Entering your vehicle's Vehicle Identification Number (VIN) on a parts website like Ford's or a reputable auto parts retailer's site can identify the engine and its specifications.
Once you know your engine type, search online for "[Your Engine Size] Ford Econoline 150 spark plug gap" to find the correct information. Don't rely on a general answer; the gap can vary significantly between engine types.