Oldsmobile/Buick Repair: fuel system, schrader valve, fuel rail

Question
I want to replace a fuel injector; someone said I have to release the pressure in the fuel line.
Pete Lacey (one of the ALLEXPERTS) said to loosen the gas cap.  I didn't know the fuel pump in the tank would pressurize the tank. Is he right?  I am concerned about the fuel rail being under some pressure under the hood and my getting a face full of fuel. Pete Lacey is "maxed-out", that is why I am asking you.
thanks.

Answer
Yes, Loosen the gas cap. Have you not ever heard a whoosh sound when you removed the cap ?. Also look on the fuel rail for a schrader valve that usually has a plastic cap on it. Remove the cap and put a rag over the schrader valve (just like a tire valve) and push down on the center of the schrader valve as if you were letting air out of your tire and some gas will come out and be absorbed into the rag(s).

WHY are you replacing it ?. How did you determine it is faulty ?.

What YEAR-MAKE-MODEL of vehicle do you have and what size engine.


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