I would check out the cold start valve for starters. Below 50 degrees F, it provides a quick spray of fuel to get the engine started. You can pull it out, plug the hole, reconnect the wire and fuel line, stick it it a jar and watch for a spray when the starter is cranked.

If that is OK, then see if the warm-up compensator has power and check for resistance across the pins where the power plugs in. Make sure the vacuum line is connected.

If that's good, then you may have a fuel distributor problem or an overly lean mixture setting. The next tests would be to test the CO at hot idle, and hook up a gauge and test the control pressure as the engine warms up from a cold start.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe