Rough Running 97 burb

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by 99buckshot, Apr 17, 2012.

  1. 99buckshot

    99buckshot New Member

    I have a K1500 5.7l 4x4 suburban. The last week or so it's been idling rough, but smooths out once it warms up. Yesterday, it started rough and kept getting worse. Then my SES light started flashing. Not just on constant, but flashing. I shut it down to avoid any damage (hopefully). I should also mention that I replaced the thermostat about a month ago. I've been trying to get all the air out of the cooling system, but still get some gurgles in the overflow tank when I shut down. When the stat went bad, it got up to about 240 on the guage, but I shut it down as quick as I could. I'm hoping this is a fuel issue, but afraid it's more serious. Any thoughts?
  2. 99buckshot

    99buckshot New Member

    Just checked fuel pressure. running 15-40psi. should be 60. guess I'll drop the tank and replace the pump and related parts.
  3. moogvo

    moogvo Epic Member 5+ Years 1000 Posts

    Flashing light indicates a condition that will harm the cats. Rich fuel usually. When it flashes at you, you need to shut it down to avoid damage. gurgling back into the coolant overflow bottle is not good. That can indicate a blown head gasket. You should let it cool, drain the radiator to half and use a block tester to look for CO2 in the coolant. If the fluid stays blue in the block tester, you're good. If it turns yellow, you're going to be doing heads.
  4. janikphoto

    janikphoto Rockstar 3 Years 100 Posts

    I sure hope you didn't blow a head gasket. That just isn't a fun way to spend you time and/or money. Maybe you'll luck out, and find out it's OK, but yeah... do a test on the heads soon.
  5. ejohnson03

    ejohnson03 Epic Member 5+ Years 1000 Posts

    Change out the fuel filter.

    Cheap item to test, if still running rough, your not out a lot of money.
  6. janikphoto

    janikphoto Rockstar 3 Years 100 Posts

    I agree with this suggestion! A lot of us have seen a dramatic improvement with just a filter change. Cheap fix, quick to do, needs to be done every couple years, anyway!
  7. MrShorty

    MrShorty Epic Member 5+ Years 1000 Posts

    In addition, I would hook a scanner up to it and see what codes the PCM has stored.
  8. moogvo

    moogvo Epic Member 5+ Years 1000 Posts

    The running issue could be caused by a fuel filter, but that wouldn't make the coolant gurgle up into the overflow when he shuts the truck off.
  9. 99buckshot

    99buckshot New Member

    Changed the filter. Still ran rough. Ended up changing the pump as well. Testing the fluid today for CO2. Fingers crossed....
  10. bazar01

    bazar01 Rockstar 100 Posts

    That is the right test. I would also do a compression and leakdown test. One or two cylinders are probably dead due to head gasket failure or warped cylinder head.
    Good luck!

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