Engine stalls, sputters and backfires when fuel tank is below half a tank

1CHEVY

MEMBER
2001 CHEVROLET EXPRESS
5.7L
V8
AUTOMATIC
150,000 MILES

I noticed the van started to hesitate after getting a little under half tank of gas. A couple of times it has completely shut off. I can pull over turn off for just a couple of minutes and crank back up and takes off fine. However, it will go back to the same thing. I recently refilled at half a tank, but it started to do the same thing at about three quarters of a tank. This van is used for deliveries all day. Seems to also start to happen around 2:00 to 3:00pm. Cleaned MAF and Throttle. Replaced fuel tank a injectors a few months back. Any idea what this could be?

Express van 3500

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

Have you checked fuel pressure? It almost sounds like either the filter is partially plugged, or the pump is weak. Take a look through this link. It explains how to test pressure. Let me know if you have done it or if you haven't, if you are comfortable doing it.

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

Also, let me know if it restarts right away after it stalls. That could be an indication of the crankshaft position sensor.

One last thing. If you have a scan tool with live data, let me know the short-term fuel trims and what the ECT (coolant temperature sensor) signal is saying the temperature is.

I will watch for your reply.

Joe