I have a 99 f150 4.2l v6 manual that has a p0174 and a b1359. I need help figuring out what are the causes for the codes. For the lean code (p0174) I've already checked for vacuum leaks and intake leaks and have had no luck, I suspect the o2 sensors because I don't trim fuel unless I rev the engine to about 4500 to 5000 rpm. And for the b1359 im unsure what is the cause I think it may just be the fuel pump or filter, but I need help

 

First check the GEM and see if it is wet for the B1359.

Is your ignition switch working ok?

The P0174 might mean a restricted fuel filter or your fuel pump is going if you can't find any vacuum leaks.