If your car has the Regina FI, as Andy suggests, it may have somehow missed a TSB from 1990, regarding Cold Start Problems. Your dealer should be able look it up (it's from January 1990, Group 23, No. 135), but here's a summary---

"Below 23°F (—5°C) cold start difficulties...rich fuel mixture during cold start crank and warm-up"

Before chasing this down, you can tell if this TSP has been applied (or not) by checking the wires at the CS Injector plug.

Peel back the rubber boot.
If the 2 connected wires are Gray-Black and Blue-Green, the TSP has NOT been applied.

If the wires are Gray-Black and any other color (with Blue-Green cut off and taped back -- or removed --) the TSB HAS BEEN applied.
NOTE: This rewiring will cause a permanent 3-2-1 OBD code, but no CE Light.

Background: The CSI has voltage is applied from the Radio Suppression Relay, like the regular injectors do. And is controlled on the ground side by the ECU, based on temperature.

The TSB changes the CSI's voltage source to an auxilliary terminal on the starter solenoid. So the CSI now gets activated only during cold cranking, rather than as soon as the Key is turned on for that 1-2 second pump buzz — and all during warm-up, till warmed above the "cold start" temp criteria.

This is all inference on my part, as the TSB offers no detailed explanation.
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Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.