After market manuals are not accurate or specific enough for all car applications and they try to cover too many models just to sell a "manual". Also they have very limited useful information on specifics for diagnosing a problem, just general information.
Some Fords use a low pressure pump intank and a high pressure pump on the frame. Others use a frame mounted high pressure pump while others use high pressure intank Assembly. You have to go by what you have in your application.
dmorris is correct in his statement that the pressure is checked at the schreader valve.