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Rough idle, shakes, stalls

Tiny
JEFFROHOTROD1985
  • MEMBER
  • 2004 GMC YUKON
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 280,000 MILES
The SUV listed above was given to me because they though it had a blown head gasket. There was no water in oil, oil in water or smoking so I didn't think it was. We knew the intake gasket was bad so I replaced the intake gasket valve cover gaskets plugs and wires but it has made no difference. It will start right up but idles so bad the entire vehicle shakes. When you put it in gear and try to go it will shut off. What could be causing this? Thanks
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Sunday, March 1st, 2020 AT 7:44 PM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,133 POSTS
Hi,

Are there any trouble codes? Have you checked engine compression or fuel pump pressure?

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

https://www.2carpros.com/articles/how-to-test-engine-compression

Also, there could be an exhaust restriction. It isn't uncommon for the converters to plug.

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Rather than removing the entire converter, remove an upstream O2 sensor to see if it changes how it runs. If you notice improvement, chances are the converter is plugged.

Let me know,
Joe
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Sunday, March 1st, 2020 AT 8:03 PM
Tiny
JEFFROHOTROD1985
  • MEMBER
  • 12 POSTS
No trouble codes. I have not checked the compression or fuel pressure the fuel pump was replaces not to long ago. I was wondering about the catalytic converter? I will pull the o2 sensor tomorrow and see if that does it. Thank you
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Sunday, March 1st, 2020 AT 9:13 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,133 POSTS
Happy to help. Keep in mind, there could be a problem with the fuel pressure regulator. Too much fuel can be an issue as well.

Take care and if you have the chance, let me know what you find.

Joe
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Sunday, March 1st, 2020 AT 9:29 PM
Tiny
JEFFROHOTROD1985
  • MEMBER
  • 12 POSTS
Hello, so I have replaced the fuel filter and it runs good enough to drive around the block. But it is still rough and tries to to shut off occasionally. Took the front o2 sensors out and could not tell a difference. I got a fuel pressure tester and it reads 48 koeo around 46 at idle. Mil has came on with a p0300 misfire.
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Tuesday, April 14th, 2020 AT 3:52 PM
Tiny
JEFFROHOTROD1985
  • MEMBER
  • 12 POSTS
It idles around 520 if I bring it up to at least 900 it does smooth out some. I also have the live data if that would help any.
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Tuesday, April 14th, 2020 AT 3:56 PM
Tiny
JEFFROHOTROD1985
  • MEMBER
  • 12 POSTS
And now I have a p0101 so maybe the MAF sensor is all my problems?
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Tuesday, April 14th, 2020 AT 3:58 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,133 POSTS
It is very possible. However, there are other things that can cause this code. If you want, take a look at the two pics I attached. They are diagnostic flow charts specific to this code. I'm just offering it in the event you want to confirm the MAF is the issue.

Let me know if I can help.

Joe
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Tuesday, April 14th, 2020 AT 5:45 PM

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