2008 Saturn Astra, Manual, RPM Sag/Stutter at idle after warm-up

saturn
astra

#1

Greetings,



I have an '08 Saturn Astra (manual transmission) currently ~50k though issue noted ~20k.



I have an issue I’d like help with.



I’ve noticed this perhaps once a month now - typically after getting off the freeway and coming to a stop at a light I will idle at about ~900-750 (normal) - then for a second or so it will drop to ~500 and stutter - and recover fine, I don’t even have time to goose the peddle if I wanted to. Once it occurred while I was idling in my driveway - slight uphill incline - and it actually stalled.



I can only confirm it happening when the car is stopped.



I am not positive but I think this may happen while I am moving as well - but it is so brief - but I have glanced and seen rpm come back to about idle.



This has occurred and without the A/C engaged.



Engine light has not been on other than to prompt the replacement of the Cam Position Sensor in the middle of this period.



When there was a dealer to take it to they had no input as there was nothing additional to work with diagnostically (they said).



Ideas?