Where can you find the vacuum hose diagram for a 1999 Mazda Protege ES 1.8 liter?

You can find the vacuum hose diagram for a 1999 Mazda Protege ES 1.8 liter in the vehicle's service manual, which can be purchased or accessed through online platforms like eBay or Amazon. Additionally, automotive forums, websites like Mazda-specific enthusiast sites, or repair databases such as Alldata or Mitchell1 may have the diagram available. Another option is to check under the hood, as some vehicles have vacuum diagrams affixed to the engine compartment.