I have a 1997 Ford Explorer 4x4 that is having issues. When I got the truck used, it was having lean code issues. I had to replace all the plugs (so old the porcelain was cracked on 2 of them), and that resolved the issues. 16 Months go by, and I have the code back. Turns out the mechanic missed the factory original plug wires, so I had to have the plugs and wires replaced. NOW I am having a P0401 code. Is this something I can fix myself? (I have not touched a vehicle mechanically sings High school in the 80s) How hard is this to fix? If so, where can I find tutorials to do this so I don't make a bigger problem/mechanic bill for myself... Any help is appreciated...