I have a 97 ford ranger and these codes came up. They are "system too lean Bank 1 & 2. The engine misfires when it is idling also. This is leaning toward the fuel filter but I don't want to just change a bunch of stuff to see if it will fix it or not. The local shops would charge around $45 to look at it and tell me what's wrong. Any suggestions as to what might be causing it? The fuel filter doesn't seem too difficult to replace besides needing the fuel line remover tool.