First time i have checked the fuel pressure on a TPI car. I hooked the gauge to the rail and had a reading of 20psi. Started the car and had a reading of 36psi. Does anyone know if this is the right way or do u have to disconnect the vacum line to the regulator.

 

YOU DID IT RIGHT. THE FACTORY CALLS FOR 34 PSI, NO LESS. A TRUE READING IS WHILE THE CAR IS RUNNING. MY '87 TPI HAS ONLY 27 PSI SO YOURS IS GOOD TO GO.

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1987 CAMARO IROC-Z 350TPI
1981 CAMARO Z-28

 

you should really disconnect the vaccum hose to the AFPR, plug it, and then that will give you the best reading. Then you should leave the guage hooked up and drive around at WOT to see if it reads the same with the vaccum line disconnected.