Starts but will not stay running

1989 GMC SIERRA
150,000 MILES • 5.7L • 4WD • AUTOMATIC
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MARK ROBERTS2
  • MEMBER
  • 1 POST
Starts up runs for two to three minutes then shuts off. Starts right up runs, again two to three minutes then shuts off. It did start up gave it gas missing bad and then shut right off. I did not check pressure for the fuel pump. I did replace fuel filter, coolant temperature sensor, throttle position sensor, fuel pump comes on. I do not think it is the fuel pump relay. Could it be the fuel pump going bad? For a 1989 GMC #2500 5.7. Help!
Dec 4, 2018 at 11:51 AM
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DANNY L
  • ✓Experienced Mechanic
  • 5,648 POSTS
Hello, I am Danny,

It is possible the fuel pump or the throttle body Injectors are going bad. The fuel pump is located in the fuel tank and the throttle body injectors (2) are located in the throttle body. If you perform a fuel pressure test it should be between 9-13 P.S.I. I have attached a tutorial showing how to test for fuel pressure. If you do not have one your local auto parts stores have tool loaner programs and will rent you one. I have also attached a picture of the throttle body Injectors. Hope this helps and thanks for using 2CarPros.
Danny-

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
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Dec 5, 2018 at 4:50 AM
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