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Rough idle and stalling on 2015 Acadia Denali need advice

Joined
Jun 25, 2025
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I've got a 2015 GMC Acadia Denali that's been having rough idling and occasional stalling when stopping. The check engine light came on with codes P0507 and P0302. I cleaned the throttle body and replaced the spark plugs, but the issue keeps returning. Sometimes the engine hesitates under light acceleration too. Has anyone dealt with this or have ideas on what else I should check? Appreciate any advice
 
@powerdriveGMC761 code P0507 is usually a vacuum leak, especially if it's struggling with a rough idle and stalling.
Check all your vacuum lines super carefully. yeah, even tiny cracks can cause big headaches.
Pay extra attention to the PCV valve and hose, a failing PCV can cause both vacuum issues and oil consumption, which might contribute to your P0302
 
I've got a 2015 GMC Acadia Denali that's been having rough idling and occasional stalling when stopping. The check engine light came on with codes P0507 and P0302. I cleaned the throttle body and replaced the spark plugs, but the issue keeps returning. Sometimes the engine hesitates under light acceleration too. Has anyone dealt with this or have ideas on what else I should check? Appreciate any advice
I agree with @PawsomePal. The codes point to a vacuum leak somewhere. If not that, then consider looking at the Mass Airflow Sensor for cleanliness or proper function and also the fuel pressure regulator as those can cause similar issues.
 
Just checking in for an update on this issue. Since you've already changed the plugs for the P0302 code, try swapping the cylinder 2 ignition coil with another 1 to see if the misfire follows the coil.
 
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