1999 E300TD when idling below 650 RPM on OBD2 is displaying EGR then 10 seconds later it Displays P0100 Unmetered air leak Wiring Connectors then the CEL lamp turns on.

If I keep the RPM above 650 I do not get CEL or P0100,
However once I stop at an intersection in gear the RPM drops to 630 and 10 seconds later the CEL lamp turns on.

This began after the upper radiator hose blew off.

180,000 miles

Where / How do I diagnose the error?

Looking for Advice
Is it possible that the radiator fluid got sucked into the vaccume filter located about 6” from the horsepower that blew off the radiator?

Hose Clamp blew off radiator near vacuum filter while driving

I noticed that my boost-vacuum sensor hose goes to EGR tube “MAP” does nor change its value on OBD2 diagnostic tool,
Shouldn’t I see a change in value vacuum or turbo boost?

Could this be the P0100 cause at low idle?
My vacuum is 22 bar at idle