I changed the PE-RPM to 1200 while reverting to my guesstimated AE settings. A first drive looks like this has cured the problem.

But I won't know for sure unless I got a WB o2 under the car and did some actual, structured test driving instead of a random cruise through town.

EDIT: Additionally, I found a factory-fresh MAP sensor in my parts pile. Will install it over the weekend and check if that changes MAP readings, just to be on the safe side.