Okay I have a 2003 ford f150 4.6 single cab short wheel base 4wd I changed fuel pump twice new filter new relay and new fuse still dont crank when checking valve on fuel rail doesn’t seem to have pressure and fuel pump doesn’t seem to be cutting on inertia switch seems to be fine ?? Not sure where else to look

 

Doesn't crank or cranks but doesn't start?

 

cranks but doesn’t start crank under starter fluid

 

cranks or doesn't run?

2 different things..... if it cranks, it's a fuel issue. if it is not cranking, it's a starting issue

what fuel pressure do you have at the rails?