Stumbles at idle

Mrhavasu

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I am thinking this may be normal, but gonna ask. So my car will stumble a bit sometimes
after first starting it, only at idle and the car is warm. Never does this while underway and does not do this again if I come to a stop and idle. It has never died and no check engine lights.
100 percent stock, Normal?
Thanks

 

J. Kidd

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I notice this occasionally as well....more like the idle drops a bit low an then gets kicked back up. And usually just during the first few minutes of driving. Never had an issue.
 

mephim

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Want to report that I was dealing with this for at least a year. It turned out to be the Evap canister purge valve had failed in the open position. This was causing small misfire counts across all 8 cylinder, leading to low idle and stumbles on startup. I was also having long crank issues after refilling fuel.

hoping this helps someone
 

Postal Bob

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I notice this occassionally. I chalk it up to the fact the the gas sitting in the fuel lines on the engine, heat up after turning off the car, and create a slight, temporary vapor expansion. You ever look at your intake air temp when the car is sitting idling during a hot summer day? My typically will go above 150°. Ever see a plastic storage gas contaner that's been sitting in a hot garage? It starts to expand like a balloon. So the same thing happens in your car's fuel lines after you turn off your car, and the engine's heat continues to heat the fuel lines. If turned back on within a few minutes, you'll notice the stumble. But if left off long enough, everything cools down and the gas pressure in the fuel lines goes back to normal.

Btw, because of the heat generated by this engine, after doing some spirited driving, when I arrrive home I open up the hood. I leave it open until everything cools down before I put it away, or cover it back up.
 

Nfs1000f

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Yes
 

MCS

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I had this issue after the Supercharger was installed. Turned out to be 2 plugs were faulty.
 

 
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