Cold Start issues, '89 200Q MC2

[Larry C Leung]

Looking for list help.

Patient, '89 200Q, MC2 198K miles

Symptom. Hard Cold Start, won't idle until car gets warm. 

No codes thrown. Output tests make Cold Start Valve click 
By symptoms only (again, no codes shown), it suggests a bad
coolant temp sensor. Soooo:

Checked continuity of the lead to the sensor, read about 12 (!) ohms
at the connector. Cut wire back and replaced the connector, now reads
0.3 ohms. Cleaned the sensor(s) with contact cleaner and checked cold 
and hot values, cold reads between 1000 to 1100 ohms (slightly out of
spec) 
warm drops to around 80 ohms, which is in range. The sensor in the
coolant flange 
reads quite similarly, so just for fun, swapped wires. No changes in
symptoms. 

So, has anyone checked their cold start valve for function? How to do it?
Is it a typical failure for the kind of milage of the vehicle. And
finally, what's
one worth and is it even worth the bother to consider a used one?

This car has been regulated to daily driver (one step over beater)
status,
so I'd rather not spend too much if possible, but will to keep it
running, so
any advice would be appreciated. 

TIA,

LL - NY