2017 El limited rpm shudder at stop light?

[OGBobbyJohnson]

Hmmm. I don’t ever catch rpms dropping. Don’t notice on window switches either.

 

[Mean_Dean]

@OGBobbyJohnson
@coolzzy @Mean_Dean

Finally caught it on my wife’s 2016 limited when I was at a red light and pulled up on window switch. This what yall talkin about? Slight vibration when the rpms dip also

Yes exactly, didn't notice at first but there is a slight dip in RPM's, like maybe 100 or so. Doesn't always do it at a light when I stop but always if I pull up on the window switch. Like the extra current draw is causing the RPM's to dip for a second until the electrical system catches up.

 

[JExpedition07]

Sure it’s not the compressor clutch engaging adding load on the serpentine belt? Will cause momentary drop in rpm while engine compensates for new load.

 

[OGBobbyJohnson]

It doesnt seem to do it any other time, only when stopped and foot on brake.

 

[bobmbx]

It doesnt seem to do it any other time, only when stopped and foot on brake.

Thats the exact time the engine has the least momentum. Small loads have a larger effect. At 2000 rpm, you won't notice it.