question on E30 MAF sensor

[laryball]

Hi The car is a 1991 318iC, M42.
The problem is bad idle at low temperatures. Car starts perfectly. Initial idle is at 900-100 rpm then goes down to ~500 rpm and will either die or "catch" and briefly rev to 1000 before dieing down again. This will repeat until it dies or warms up. If I give it gas it runs fine.

all vac hose including those under the intake manifold replaced. ICV replaced, temp sensor for DME replaced. Engine idles better when cold with MAF unplugged.

MAF connector is 5 pin arranged in a 3/4 circle (photo). Assign pin 1 to most ccw pin. Pin 1-2 R = 2647 ohm. Pin 4-5 1160 ohm with flapper door closed. With flapper door just cracked open it goes t0 ~400 ohm. With it open more it goes to 650-700 ohm throughout the range. I don't have the specs on these; don't even know if I'm testing the right pins. I assume i set is temperature sensor (photo) and 1 set is the variable resistor.

It's an expensive part. I'd like to test before I buy blind. I'm off to buy MAF cleaner to see if that helps.

thanks for any help.
2 photos attached