The fuel pressure specification for a 1999 GMC Jimmy varies slightly depending on the engine. You must consult your owner's manual or a reliable repair manual specific to your Jimmy's engine (4.3L V6 or 5.7L V8 are the most common).
There's no single, universally accurate answer here. Providing the wrong pressure could damage your fuel system. Using the wrong information from an online forum could lead to serious problems. Always refer to your vehicle's documentation.
