Fuel pump problem?

MILK30

MEMBER
1999 CHEVROLET SUBURBAN

I have a 1999 Chevy Suburban with a 5.7 Vortec enigine and 151,000 miles on it. For about a week the truck would stumble at part throttle. Scan showed O2 sensor/ changed that and fuel filter. Check engine light scanned again and showed manufacturer ignition problem or misfire. Then after putting 25 gallons of gas in truck the engine shut off going down the road. Fuel gauge went to past the full mark pointing almost straight down. Checked fuel pump relay - was fine. Decided must be fuel pump - replaced fuel pump and connector. Reinstalled fuel tank, reconnected battery and still does not run. Please help!

1 Reply

PEAR69

MECHANIC
1,482 POSTS

What tests did you do to determine that the poor old fuel pump was the problem?

This guide can help

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

If you have low or high fuel pressure it will be a blocked filter either inside or outside the tank or a bad pressure regulator.

Check the fuel pressure it should be around 66psi. What are the actual codes? P0???? Check the air filter.

Look for a throttle body leak. And have your cat.converter flow tested. Sounds like there is a clogged fuel line or a clogged exhaust,,usually a cat.converter...Let me know how you make out.