Whydoesmy car stall on the highway when at speed I shift from gear into neutral? on 2008 Nissan Sentra

Whenever I am driving at highway speeds and I shift into neutral (e.g. when I need to slow down), the rpms suddenly drop from around 2500-3000 to almost zero. Sometimes the engine recovers and doesn't stall, other times the engine quits cold turkey. This has happened to me more than a handful of times. I've learned to deal with it, but I'd like to know what the problem is. It doesn't matter if the weather is hot or cold. I thought it might be the Idle Air Control Valve, but now I'm not too sure.

1 answer 2 comments
Check engine light on?
Check engine light is not on.
Needs to be scanned so live data can be seen. IAC is one possibility. More exist but cant guess at it.