Question

on my 1997 Mazda Protege with multiple codes, should you always address them in order? (The order they're listed on the scan tool). I have the engine code P0300, P0140, and P0335

Answer 1

You can repair it in any order you like if they are not related. I suggest start with the easy and cheap ones first

P0300- is a misfire code, start by using 91 octane gas, replace spark plugs and wires

P0335 is a Crankshaft Position Sensor, start by checking the battery charging system

P0140 - Oxygen Sensor  Bank 1 maybe be bad