2002 GMC Yukon Rattle noise

NLPONCE7

MEMBER
2002 GMC YUKON
AUTOMATIC
167,000 MILES

Rattle noise when I turn my AC on and pushing at the gas pedal. Once I take my foot off the pedal it will stop. Only rattles when the AC is on. If the AC is off and im pushing on my gas pedal there is no noise. Advise please.

Monday, August 4th, 2014 AT 3:35 PM

5 Replies

FREEMBA

MECHANIC
1,152 POSTS

Could be "spark knock" which is the premature detonation of the fuel in the cylinder often caused by excessive temperatures in the cylinder (engine running hotter than normal), ignition timing advanced too much (this is computer controlled so its not likely the problem), poor quality fuel, etc.
Have you noticed the temperature gauge when this is happening?
Are you using the same type fuel as before (when it didn't rattle)?

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Monday, August 4th, 2014 AT 4:13 PM

NLPONCE7

MEMBER
3 POSTS

Hi! Yes I have been checking the temp gage & it stays normal. Been using same cheveron unleaded gas.

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Monday, August 4th, 2014 AT 7:00 PM

FREEMBA

MECHANIC
1,152 POSTS

Is you check engine light on? If so have the codes read and post them here for more help. Many parts stores read the codes for FREE.

With the truck in PARK and the engine running, turn the a/c on a push the gas a couple of times to see if you hear the noise. Let me know what you find.

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Tuesday, August 5th, 2014 AT 6:27 PM

NLPONCE7

MEMBER
3 POSTS

Hi, Engine light is not on. I did run the truck in park with AC on high and pushed on the gas a few times at 5pm. No noise. It's only when I start driving off it makes the rattle noise while the AC is on. Then when I take my foot of the gas pedal it stops and then after a few mins of driving it will stop. I did notice that in the mornings around 715 when I turned my AC on driving off it doesnt make the rattle noise.

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Thursday, August 7th, 2014 AT 9:09 AM

FREEMBA