Another reason to stay away from Chilton and Haynes. 55-61psi is for 94 MFI systems, those guys are a few years behind. GM "dealer issue" factory shop manual states 60psi to 66psi and remain above 55 psi for 3 to 5 minutes after the pump shuts off. GM does not publish any "engine running" fuel pressure specs for CSFI systems, too many variables.