Runs rough at start up

2002 GMC YUKON
275,000 MILES • 5.3L • V8 • 4WD • AUTOMATIC
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KEVIN MARLOW
  • MEMBER
  • 1 POST
Seems to be worse under one-fourth tank. Black smoke when accelerating. Black carbon with moisture coming out of tailpipe.
Jun 6, 2022 at 4:31 PM
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STRAILER
  • ASE Certified Mechanic
  • 54,837 POSTS
  • ASE Certified Mechanic
Yes, this happens when the fuel pressure starts to get low due to a weak fuel pump or clogged fuel filter if your truck has one. To be sure, here is a guide on how to check the fuel pressure and instructions on how to change the fuel pump out if needed, if you are going to get a new fuel pump unit, please get an AC Delco unit from Rock auto they are a few dollars more but worth it.

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

Here is how to change the fuel filter out with instructions after the fuel pump images below:

https://www.2carpros.com/articles/how-to-change-a-fuel-filter


Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.
Jun 7, 2022 at 9:28 AM
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