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GM Master Denny
GM Master Denny, GM Master Tech
Category: GM
Satisfied Customers: 178
Experience:  GM and ASE Master Tech, ASE Advanced Level L1, 15 years experience
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2005 GMC Yukon has a rough idle and a slow speed or stopping.

Customer Question

2005 GMC Yukon has a rough idle and a slow speed or stopping. SES light is on. This has been progressive problem that used to be fixed by turning the truck off and then back on, or tightening the gas cap. However for the last 2 days, nothing will fix the issue?
Submitted: 7 years ago.
Category: GM
Expert:  GM Master Denny replied 7 years ago.
You need to find out what the trouble codes are first. You can take it to your local Autozone and they can check the codes for you. They will do this free of charge. Let me know what codes are coming up. I'm thinking you might be having a throttle body issue, but let me know about the codes . This will help me get you on the correct diagnostic path.
Customer: replied 7 years ago.

Great, I will go do that right now and then email you back!


Lindon Dewey

Expert:  GM Master Denny replied 7 years ago.
Not sure how long I will be on here tonight, but I will have a response first thing in the AM if I'm not on when you reply.
Customer: replied 7 years ago.

I went to my local advanced auto store and I got 4 codes (listed below). Ironically once the error codes were cleared the problem went away. I know that they will be back, because they always come back. When the problem started about 18 months ago I took it to the dealer and they told me that is was the intake gasket before they even ran the codes on it. Ironically they also diagnosed the SES light when the vehicle was 6 months old as a loose gas cap. In the last 18 months I have been able to turn the truck off and restart it or reclose the gas cap to stop the SES from showing up. In early October this 2 day problem started suddenly and ended just as suddenly. My typical fixes did not reslove the problem, it just went away on it's own. On Sunday afternoon the promblem reoccured and did not resolve it's self until I drove it to Advanced Auto tonight. It happens on the cold start, while it warmed up, occassionaly when I turn the car off it smells like rotten eggs - like it is running to rich. I don't beleive it is the intake gasket because the problem is intermitant. Once I reach speeds of 25 - 75 the problem does not affect the preformance of the vehicle, only when I slow for a stop sign, light etc.


Error Codes:


P0171 System Too Lean Bank 1


P0300 Random/multiple cyc misfire detected


P0131 02 sensor circuit low volts bank 1 sensor 1


P0300 Random misfire cyc misfie detected



Lindon Dewey

Expert:  GM Master Denny replied 7 years ago.
I am going to need the VIN for the vehicle. The numbers are on the lower left side of the windshield,on a tag on the drivers door jamb, or on your vehicle registration.
Customer: replied 7 years ago.

Sorry for the delayed reply, I was out of town for the day.


VIN: 1GKEK13T55J138571


Thank You,

Lindon J Dewey

Expert:  GM Master Denny replied 7 years ago.
I am having technical problems with the site today. I will post the answer as soon as the tech people can resolve this. Thanks, Denny
Expert:  GM Master Denny replied 7 years ago.

Ok, I have a couple of bulletins for you to check out.


Subject:Cold Engine Idle Misfire or DTCs P0171 P0174

Models:2002-2005 Cadillac Escalade
1999-2005 Chevrolet Avalanche, Express, Silverado, Suburban, Tahoe, Trailblazer
1999-2005 GMC Savana, Sierra, Yukon
2003-2005 Hummer H2


This PI was superseded to update parts information. Please discard PIP3232A.


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.


99 through 05 GEN III truck engines may experience any of the following:

  1. A cold rough idle that diminishes as the engine warms up.
  2. Possible DTCS P0171, P0174, or P0300.
  3. Random misfires at idle.


The intake gasket seals may be leaking around the intake ports, causing a lean condition. The intake gasket seals may leak around the bottom side of the port, making it a challenge to detect the vacuum leak. The technician may also notice lower than normal MAF readings if the intake seals are leaking.

  1. If leaking intake gasket seals are found, replace the intake gaskets. During the repair be sure to use the current GMSPO part number for replacement intake gaskets. The current GMSPO part number for intake gaskets will have a teal green intake gasket seal. The old version of the intake gaskets were orange in color. Use only the teal green colored gaskets for a repair.
  2. The intake plenum should also be checked for excessive warpage that may cause an uneven clamping pressure of the seal. If the plenum is found to be warped it will need to be replaced. Service Information states, "An intake manifold with warpage in excess of 3 mm (0.118 in) over a 200 mm (7.87 in) area should be replaced". Intake warpage is measured at the gasket sealing surfaces, and should be measured within a 200 mm (7.87 in) area. This measurement is across only two of the intake runner port openings. Measurements taken across the entire distance of all four intake runner ports will lead to unnecessary manifold replacements.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.






Subject:LM7, L59 or L33 Engines with Cold Start Rough or Incorrect Idle, Misfire, Malfunction Indicator Lamp (MIL) or Flashing Requiring O2 Sensor Replacement (Reprogram PCM)

Models:2004-2005 Cadillac Escalade
2004-2005 Chevrolet Avalanche, Silverado 1500, Suburban, Tahoe
2005 Chevrolet Silverado Hybrid (HP2)
2004-2005 GMC Sierra 1500, Yukon, Yukon XL
2005 GMC Sierra Hybrid (PH2)
with Vortec 5300 5.3L V-8 Engine (VINs T, Z, B -- RPOs LM7, L59, L33)




Some customers may comment on a Malfunction Indicator Lamp (MIL) On or that the MIL is flashing. An actual engine misfire may or may not be felt along with an incorrect idle speed. Typically this occurs during cold winter months, on cold engine starts. Some vehicles may have been previously serviced for the same condition. Technicians may also find the following DTCs stored with the Tech 2® P0131, P0133, P0134, P0137, P0138, P0140, P0151, P0153, P0154, P0157, P1133, which may be in conjunction with P0171, P0174, P0300 and P1138.


Water shock occurs when water droplets are present in the exhaust. The water in the exhaust contacts the sensor element inside the HO2 sensor, causing the HO2 sensor element to crack.


Upon diagnostic investigation, the technician may find that the HO2 sensor requires replacement. In addition to replacing the affected HO2 sensor, these vehicles should also be reflashed with the latest PCM calibration. An updated PCM calibration will be available to dealerships as part of TIS 2000 incremental satellite update 11.0 (NAO version 25.010) or greater. Always, make sure your Tech 2 is updated with the latest software version.

Important: If a DTC P0420 or P0430 is stored along with DTC(s) P0300, the catalytic converter diagnostics in Service Information (SI) must be followed to determine if the catalytic converters are operating properly.







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Customer: replied 7 years ago.

I took the truck to Advanaced Auto had the codes read. Once that was done my husband went a bought an O2 sensor and replaced that. Thank you for your reply, it is exactly what my husband thought it was, your answer confirms that our dealer should have given us better advice. By paying you and buying the 02 Sensor I think we saved an unneccessary repair bill.