starting problems fuel pressure

fuel pressure with key on is 55-60 psi .while cranking engine and pressure stays in this range 1999 jimmy starts when cranking pressure sometimes drops to 40-45psi doesn't want to start worth a hoot! is problem fuel pump or pressure regulator? lines are in good shape any thanks.

Ony way to tell is pinch off the return line but the pumps were usually the issue.

Your fuel pressure is too low. Key on, engine off, fuel pump running, fuel pressure must be 60psi to 66psi and must remain above 55psi for 3 to 5 minutes after the pump shuts off. Check for battery voltage and good ground at the fuel pump, (very important). If it turns out that the pump is faulty, don't waste your time and money with an aftermarket fuel pump. Lifetime warranty is nice, but wouldn't you rather do the job once and be done with it? Spend the few extra bucks and install an AC Delco pump.

thanks for quick response excellent info going to replace fuel pump will report progess

changed fuel pump with new delphi around $300 fixed all starting issues took 2hrs. pressure steady at 60psi thanks fellas

Success... glad you got her going, and thanks for posting back with the fix.