My Lada did this because the carbon cores in the ignition leads were powdery and rendered the spark sensitive to deceleration loads, cutting the ignition.
Fancy “racing” silicone leads cured it, though I rather missed being the first kid on the block (by about 20 years?) with stop-start.
Other (perhaps more likely) possibilities include
Idle speed set too low – probably not that but worth adjusting in case
Vacuum leak – Gets my vote, mostly because I’ve had that problem on the Skywing (a much simpler vehicle) and suspect I had it on earlier bangers too but was then younger and even more clueless so didn’t work it out.
Higher Tech Stuff I have limited experience with
EGR valve stuck, so engine chokes itself at idle – Check operation (depends. I’ve only done this on a Honda Accord which was electric. Some of them are pneumatic) hit it with a hammer, clean it, blank it off (temporarily/diagnostically/permanently?), and only AS A LAST RESORT IF YOU KNOW ITS BUST and a problem, replace it
If you can figure or find out how to activate your EGR valve, assuming you have one (on the Accord IIRC it just needed jumpered to 12V supply) and fully opening it doesn't stall the engine at idle, then it probably isn't that.
Faulty Idle Air Control valve (IAC) – look it up. No experience with these. But see video below.
Dirty intake path (including MAF/MAP sensor etc where present) – CLEAN, using smelly organic solvents.
Edited by edlithgow on 29/05/2021 at 02:52
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