Joined: Nov 2018

Posts: 1

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My 2003 Chevy Suburban 1500 Z71 5.3L w/Flex Fuel is acting up. Fuel pump was replaced about a month ago. Went with the Delphi OEM pump, fuel filter, and most fuel lines also replaced (some sections with flexible nylon lines). Was fine for about 3 weeks then one day started to stall at low idle. First few times it started back up fine, then would not re-start. Towed home, tested fuel pressure and was only getting 42-45 psi when attempting to start. No fire. I worked through all the fuel lines to confirm good connections and that there were no kinks. Everything I could seen and feel looked fine. Eventually became convinced that I had a faulty new fuel pump. With tank 95% filled I decided to cut access panel to replaced the under warranty pump. Swap completed, started right up, but still only showing 42-45 psi. No check engine lights, no codes being thrown. Drove to work fine, but at about 30 mins into drive home vehicle started stalling at low idle again. No check engine lights. I know it should have greater fuel pressure, but cannot figure out why it is low. Thoughts?

Do I maybe have a control module of some sort going bad, but not throwing a code? Is one of the fuel lines in adequate due to diameter differences? What are your ideas?